Re: Slow booting on x15

Re: Slow booting on x15

[Grygorii Strashko]

On 01/10/2020 11:22, Laurent Pinchart wrote:
> Hi Tony,
> 
> On Thu, Oct 01, 2020 at 11:17:48AM +0300, Tony Lindgren wrote:
>> * Tony Lindgren <tony@atomide.com> [201001 07:53]:
>>> * Peter Ujfalusi <peter.ujfalusi@ti.com> [200930 12:41]:
>>>> Fwiw on my beagle x15
>>>>
>>>> v5.8
>>>> [    9.908787] Run /sbin/init as init process
>>>>
>>>> v5.9-rc7
>>>> [   15.085373] Run /sbin/init as init process
>>>>
>>>>
>>>> It appears to be 'fixed' in next-20200928: the board does not even boot.
>>>
>>> Yeah so it seems :(
>>>
>>>> next-20200928 on omap5
>>>> [    9.936806] Run /sbin/init as init process
>>>>
>>>>
>>>> -rc7 spends most of it's time:
>>>> [    7.635530] Micrel KSZ9031 Gigabit PHY 48485000.mdio:01: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=48485000.mdio:01, irq=POLL)
>>>> [   14.956671] cpsw 48484000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off
>>>> [   15.005211] IP-Config: Complete:
>>>
>>> Booting with initcall_debug I see this with current Linux next:
>>>
>>> ...
>>> [    1.697313] cpuidle: using governor menu
>>> [    1.701353] initcall init_menu+0x0/0xc returned 0 after 0 usecs
>>> [    1.707458] calling  gpmc_init+0x0/0x10 @ 1
>>> [    1.711784] initcall gpmc_init+0x0/0x10 returned 0 after 0 usecs
>>> [    1.717974] calling  omap3_l3_init+0x0/0x10 @ 1
>>> [    1.722653] initcall omap3_l3_init+0x0/0x10 returned 0 after 0 usecs
>>> [    1.729201] calling  omap_l3_init+0x0/0x10 @ 1
>>> [    1.733791] initcall omap_l3_init+0x0/0x10 returned 0 after 0 usecs
>>> [    1.740314] calling  gate_vma_init+0x0/0x70 @ 1
>>> [    1.744976] initcall gate_vma_init+0x0/0x70 returned 0 after 0 usecs
>>> [    1.751522] calling  customize_machine+0x0/0x30 @ 1
>>> [    3.823114] initcall customize_machine+0x0/0x30 returned 0 after 2011718 usecs
>>> [    3.830566] calling  init_atags_procfs+0x0/0xec @ 1
>>> [    3.835583] No ATAGs?
>>
>> And the long time above with customize_machine() ends up being
>> pdata_quirks_init() calling of_platform_populate().
> 
> That's what the delay is for me (I think I've reported that initially).
> 
>>> Laurent & Tomi, care to check what you guys see in the slow booting case
>>> after booting with initcall_debug?
>>
>> But maybe the long delay is something else for you guys so please check.
> 

It's all devlink :( Looks like sometimes, improvements (PM) could became so complicated
that time required to execute such algorithms may completely eliminate all expected benefits.
Will not be surprised if PM consumption also increased instead of decreasing in some cases.

not sure if it's 100% correct, but below diff reduces boot time
from 7.6sec to 3.7sec :P

before:
[    0.053870] cpuidle: using governor menu
[    2.505971] No ATAGs?
...
[    7.562317] Freeing unused kernel memory: 1024K

after:
[    0.053800] cpuidle: using governor menu
[    0.136853] No ATAGs?
[    3.716218] devtmpfs: mounted
[    3.719628] Freeing unused kernel memory: 1024K
[    3.724266] Run /sbin/init as init process  \x01

----
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 071f04da32c8..e0cc37ed46ca 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -481,6 +481,7 @@ int of_platform_populate(struct device_node *root,
         pr_debug(" starting at: %pOF\n", root);
  
         device_links_supplier_sync_state_pause();
+       fw_devlink_pause();
         for_each_child_of_node(root, child) {
                 rc = of_platform_bus_create(child, matches, lookup, parent, true);
                 if (rc) {
@@ -488,6 +489,7 @@ int of_platform_populate(struct device_node *root,
                         break;
                 }
         }
+       fw_devlink_resume();
         device_links_supplier_sync_state_resume();
  
         of_node_set_flag(root, OF_POPULATED_BUS);
@@ -538,9 +540,7 @@ static int __init of_platform_default_populate_init(void)
         }
  
         /* Populate everything else. */
-       fw_devlink_pause();
         of_platform_default_populate(NULL, NULL, NULL);
-       fw_devlink_resume();
  
         return 0;
  }


-- 
Best regards,
grygorii

Re: Slow booting on x15

[Geert Uytterhoeven]

Hi Grygorii et al,

On Thu, Oct 1, 2020 at 2:56 PM Grygorii Strashko
<grygorii.strashko@ti.com> wrote:
> On 01/10/2020 11:22, Laurent Pinchart wrote:
> > On Thu, Oct 01, 2020 at 11:17:48AM +0300, Tony Lindgren wrote:
> >>>> -rc7 spends most of it's time:
> >>>> [    7.635530] Micrel KSZ9031 Gigabit PHY 48485000.mdio:01: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=48485000.mdio:01, irq=POLL)
> >>>> [   14.956671] cpsw 48484000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off
> >>>> [   15.005211] IP-Config: Complete:

1. Is irq=POLL normal behavior for your board?
2. As this is a Micrel PHY, perhaps you are affected by the changes in
   the configuration defaults in commit bcf3440c6dd78bfe ("net: phy:
   micrel: add phy-mode support for the KSZ9031 PHY")?

See also the performance drop figures in the description of quick fix
9b23203c32ee02cd ("ravb: Mask PHY mode to avoid inserting delays twice")
(and better solution
 https://lore.kernel.org/linux-renesas-soc/20201001101008.14365-1-geert+renesas@glider.be)

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: Slow booting on x15

[Grygorii Strashko]

hi Geert,

On 01/10/2020 16:11, Geert Uytterhoeven wrote:
> Hi Grygorii et al,
> 
> On Thu, Oct 1, 2020 at 2:56 PM Grygorii Strashko
> <grygorii.strashko@ti.com> wrote:
>> On 01/10/2020 11:22, Laurent Pinchart wrote:
>>> On Thu, Oct 01, 2020 at 11:17:48AM +0300, Tony Lindgren wrote:
>>>>>> -rc7 spends most of it's time:
>>>>>> [    7.635530] Micrel KSZ9031 Gigabit PHY 48485000.mdio:01: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=48485000.mdio:01, irq=POLL)
>>>>>> [   14.956671] cpsw 48484000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off
>>>>>> [   15.005211] IP-Config: Complete:
> 
> 1. Is irq=POLL normal behavior for your board?
> 2. As this is a Micrel PHY, perhaps you are affected by the changes in
>     the configuration defaults in commit bcf3440c6dd78bfe ("net: phy:
>     micrel: add phy-mode support for the KSZ9031 PHY")?
> 
> See also the performance drop figures in the description of quick fix
> 9b23203c32ee02cd ("ravb: Mask PHY mode to avoid inserting delays twice")
> (and better solution
>   https://lore.kernel.org/linux-renesas-soc/20201001101008.14365-1-geert+renesas@glider.be)


It's not about Ethernet PHY and I've tried different board am571x-idk.

The boot delay introduced first very early during boot:

>> [    1.729201] calling  omap_l3_init+0x0/0x10 @ 1
>> [    1.733791] initcall omap_l3_init+0x0/0x10 returned 0 after 0 usecs
>> [    1.740314] calling  gate_vma_init+0x0/0x70 @ 1
>> [    1.744976] initcall gate_vma_init+0x0/0x70 returned 0 after 0 usecs
>> [    1.751522] calling  customize_machine+0x0/0x30 @ 1
>> [    3.823114] initcall customize_machine+0x0/0x30 returned 0 after 2011718 usecs
>> [    3.830566] calling  init_atags_procfs+0x0/0xec @ 1
>> [    3.835583] No ATAGs?
> 
> And the long time above with customize_machine() ends up being
> pdata_quirks_init() calling of_platform_populate().

And was narrowed down to ^ of_platform_populate() - above customize_machine() costs 2sec.

related discussion https://lkml.org/lkml/2020/6/17/452

-- 
Best regards,
grygorii

Re: Slow booting on x15

[Saravana Kannan]

On Thu, Oct 1, 2020 at 5:56 AM Grygorii Strashko
<grygorii.strashko@ti.com> wrote:
>
>
>
> On 01/10/2020 11:22, Laurent Pinchart wrote:
> > Hi Tony,
> >
> > On Thu, Oct 01, 2020 at 11:17:48AM +0300, Tony Lindgren wrote:
> >> * Tony Lindgren <tony@atomide.com> [201001 07:53]:
> >>> * Peter Ujfalusi <peter.ujfalusi@ti.com> [200930 12:41]:
> >>>> Fwiw on my beagle x15
> >>>>
> >>>> v5.8
> >>>> [    9.908787] Run /sbin/init as init process
> >>>>
> >>>> v5.9-rc7
> >>>> [   15.085373] Run /sbin/init as init process
> >>>>
> >>>>
> >>>> It appears to be 'fixed' in next-20200928: the board does not even boot.
> >>>
> >>> Yeah so it seems :(
> >>>
> >>>> next-20200928 on omap5
> >>>> [    9.936806] Run /sbin/init as init process
> >>>>
> >>>>
> >>>> -rc7 spends most of it's time:
> >>>> [    7.635530] Micrel KSZ9031 Gigabit PHY 48485000.mdio:01: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=48485000.mdio:01, irq=POLL)
> >>>> [   14.956671] cpsw 48484000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off
> >>>> [   15.005211] IP-Config: Complete:
> >>>
> >>> Booting with initcall_debug I see this with current Linux next:
> >>>
> >>> ...
> >>> [    1.697313] cpuidle: using governor menu
> >>> [    1.701353] initcall init_menu+0x0/0xc returned 0 after 0 usecs
> >>> [    1.707458] calling  gpmc_init+0x0/0x10 @ 1
> >>> [    1.711784] initcall gpmc_init+0x0/0x10 returned 0 after 0 usecs
> >>> [    1.717974] calling  omap3_l3_init+0x0/0x10 @ 1
> >>> [    1.722653] initcall omap3_l3_init+0x0/0x10 returned 0 after 0 usecs
> >>> [    1.729201] calling  omap_l3_init+0x0/0x10 @ 1
> >>> [    1.733791] initcall omap_l3_init+0x0/0x10 returned 0 after 0 usecs
> >>> [    1.740314] calling  gate_vma_init+0x0/0x70 @ 1
> >>> [    1.744976] initcall gate_vma_init+0x0/0x70 returned 0 after 0 usecs
> >>> [    1.751522] calling  customize_machine+0x0/0x30 @ 1
> >>> [    3.823114] initcall customize_machine+0x0/0x30 returned 0 after 2011718 usecs
> >>> [    3.830566] calling  init_atags_procfs+0x0/0xec @ 1
> >>> [    3.835583] No ATAGs?
> >>
> >> And the long time above with customize_machine() ends up being
> >> pdata_quirks_init() calling of_platform_populate().
> >
> > That's what the delay is for me (I think I've reported that initially).
> >
> >>> Laurent & Tomi, care to check what you guys see in the slow booting case
> >>> after booting with initcall_debug?
> >>
> >> But maybe the long delay is something else for you guys so please check.
> >
>
> It's all devlink :( Looks like sometimes, improvements (PM) could became so complicated
> that time required to execute such algorithms may completely eliminate all expected benefits.
> Will not be surprised if PM consumption also increased instead of decreasing in some cases.
>
> not sure if it's 100% correct, but below diff reduces boot time
> from 7.6sec to 3.7sec :P
>
> before:
> [    0.053870] cpuidle: using governor menu
> [    2.505971] No ATAGs?
> ...
> [    7.562317] Freeing unused kernel memory: 1024K
>
> after:
> [    0.053800] cpuidle: using governor menu
> [    0.136853] No ATAGs?
> [    3.716218] devtmpfs: mounted
> [    3.719628] Freeing unused kernel memory: 1024K
> [    3.724266] Run /sbin/init as init process
>
> ----
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 071f04da32c8..e0cc37ed46ca 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -481,6 +481,7 @@ int of_platform_populate(struct device_node *root,
>          pr_debug(" starting at: %pOF\n", root);
>
>          device_links_supplier_sync_state_pause();
> +       fw_devlink_pause();
>          for_each_child_of_node(root, child) {
>                  rc = of_platform_bus_create(child, matches, lookup, parent, true);
>                  if (rc) {
> @@ -488,6 +489,7 @@ int of_platform_populate(struct device_node *root,
>                          break;
>                  }
>          }
> +       fw_devlink_resume();
>          device_links_supplier_sync_state_resume();
>
>          of_node_set_flag(root, OF_POPULATED_BUS);
> @@ -538,9 +540,7 @@ static int __init of_platform_default_populate_init(void)
>          }
>
>          /* Populate everything else. */
> -       fw_devlink_pause();
>          of_platform_default_populate(NULL, NULL, NULL);
> -       fw_devlink_resume();

Your analysis is right, but this change is not safe. You'll get an
unlocked linked list trampling if you call it outside of where it's
called now. That's explicitly why I didn't do it the way this patch
does it.

To explain more, if you call fw_devlink_pause/resume() inside
of_platform_populate() you can end up calling it in the context of
another device's probe function. When a device's probe function is
called, a has a bunch of other locks held and you'll cause a deadlock.
To avoid that, I had to use defer_fw_devlink_lock to manage the list
used by fw_devlink_pause/resume().

I'll add more details later. But yeah, this patch isn't safe as is.

-Saravana

Re: Slow booting on x15

[Grygorii Strashko]

On 01/10/2020 21:24, Saravana Kannan wrote:
> On Thu, Oct 1, 2020 at 5:56 AM Grygorii Strashko
> <grygorii.strashko@ti.com> wrote:
>>
>>
>>
>> On 01/10/2020 11:22, Laurent Pinchart wrote:
>>> Hi Tony,
>>>
>>> On Thu, Oct 01, 2020 at 11:17:48AM +0300, Tony Lindgren wrote:
>>>> * Tony Lindgren <tony@atomide.com> [201001 07:53]:
>>>>> * Peter Ujfalusi <peter.ujfalusi@ti.com> [200930 12:41]:
>>>>>> Fwiw on my beagle x15
>>>>>>
>>>>>> v5.8
>>>>>> [    9.908787] Run /sbin/init as init process
>>>>>>
>>>>>> v5.9-rc7
>>>>>> [   15.085373] Run /sbin/init as init process
>>>>>>
>>>>>>
>>>>>> It appears to be 'fixed' in next-20200928: the board does not even boot.
>>>>>
>>>>> Yeah so it seems :(
>>>>>
>>>>>> next-20200928 on omap5
>>>>>> [    9.936806] Run /sbin/init as init process
>>>>>>
>>>>>>
>>>>>> -rc7 spends most of it's time:
>>>>>> [    7.635530] Micrel KSZ9031 Gigabit PHY 48485000.mdio:01: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=48485000.mdio:01, irq=POLL)
>>>>>> [   14.956671] cpsw 48484000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off
>>>>>> [   15.005211] IP-Config: Complete:
>>>>>
>>>>> Booting with initcall_debug I see this with current Linux next:
>>>>>
>>>>> ...
>>>>> [    1.697313] cpuidle: using governor menu
>>>>> [    1.701353] initcall init_menu+0x0/0xc returned 0 after 0 usecs
>>>>> [    1.707458] calling  gpmc_init+0x0/0x10 @ 1
>>>>> [    1.711784] initcall gpmc_init+0x0/0x10 returned 0 after 0 usecs
>>>>> [    1.717974] calling  omap3_l3_init+0x0/0x10 @ 1
>>>>> [    1.722653] initcall omap3_l3_init+0x0/0x10 returned 0 after 0 usecs
>>>>> [    1.729201] calling  omap_l3_init+0x0/0x10 @ 1
>>>>> [    1.733791] initcall omap_l3_init+0x0/0x10 returned 0 after 0 usecs
>>>>> [    1.740314] calling  gate_vma_init+0x0/0x70 @ 1
>>>>> [    1.744976] initcall gate_vma_init+0x0/0x70 returned 0 after 0 usecs
>>>>> [    1.751522] calling  customize_machine+0x0/0x30 @ 1
>>>>> [    3.823114] initcall customize_machine+0x0/0x30 returned 0 after 2011718 usecs
>>>>> [    3.830566] calling  init_atags_procfs+0x0/0xec @ 1
>>>>> [    3.835583] No ATAGs?
>>>>
>>>> And the long time above with customize_machine() ends up being
>>>> pdata_quirks_init() calling of_platform_populate().
>>>
>>> That's what the delay is for me (I think I've reported that initially).
>>>
>>>>> Laurent & Tomi, care to check what you guys see in the slow booting case
>>>>> after booting with initcall_debug?
>>>>
>>>> But maybe the long delay is something else for you guys so please check.
>>>
>>
>> It's all devlink :( Looks like sometimes, improvements (PM) could became so complicated
>> that time required to execute such algorithms may completely eliminate all expected benefits.
>> Will not be surprised if PM consumption also increased instead of decreasing in some cases.
>>
>> not sure if it's 100% correct, but below diff reduces boot time
>> from 7.6sec to 3.7sec :P
>>
>> before:
>> [    0.053870] cpuidle: using governor menu
>> [    2.505971] No ATAGs?
>> ...
>> [    7.562317] Freeing unused kernel memory: 1024K
>>
>> after:
>> [    0.053800] cpuidle: using governor menu
>> [    0.136853] No ATAGs?
>> [    3.716218] devtmpfs: mounted
>> [    3.719628] Freeing unused kernel memory: 1024K
>> [    3.724266] Run /sbin/init as init process
>>
>> ----
>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
>> index 071f04da32c8..e0cc37ed46ca 100644
>> --- a/drivers/of/platform.c
>> +++ b/drivers/of/platform.c
>> @@ -481,6 +481,7 @@ int of_platform_populate(struct device_node *root,
>>           pr_debug(" starting at: %pOF\n", root);
>>
>>           device_links_supplier_sync_state_pause();
>> +       fw_devlink_pause();
>>           for_each_child_of_node(root, child) {
>>                   rc = of_platform_bus_create(child, matches, lookup, parent, true);
>>                   if (rc) {
>> @@ -488,6 +489,7 @@ int of_platform_populate(struct device_node *root,
>>                           break;
>>                   }
>>           }
>> +       fw_devlink_resume();
>>           device_links_supplier_sync_state_resume();
>>
>>           of_node_set_flag(root, OF_POPULATED_BUS);
>> @@ -538,9 +540,7 @@ static int __init of_platform_default_populate_init(void)
>>           }
>>
>>           /* Populate everything else. */
>> -       fw_devlink_pause();
>>           of_platform_default_populate(NULL, NULL, NULL);
>> -       fw_devlink_resume();
> 
> Your analysis is right, but this change is not safe. You'll get an
> unlocked linked list trampling if you call it outside of where it's
> called now. That's explicitly why I didn't do it the way this patch
> does it.
> 
> To explain more, if you call fw_devlink_pause/resume() inside
> of_platform_populate() you can end up calling it in the context of
> another device's probe function. When a device's probe function is
> called, a has a bunch of other locks held and you'll cause a deadlock.
> To avoid that, I had to use defer_fw_devlink_lock to manage the list
> used by fw_devlink_pause/resume().
> 
> I'll add more details later. But yeah, this patch isn't safe as is.

I assume you going to fix it your way, right?

Just FYI. On ARM main DT population path is:

arch_initcall(customize_machine)
	machine_desc->init_machine();
		of_platform_default_populate();
		-- or --
		of_platform_populate();

the of_platform_default_populate_init() called later due to make/linker dependencies.

As result, existing pause/resume optimizations don't fully working.

Thank you.

-- 
Best regards,
grygorii

Re: Slow booting on x15

[Saravana Kannan]

On Thu, Oct 1, 2020 at 12:43 PM Grygorii Strashko
<grygorii.strashko@ti.com> wrote:
>
>
>
> On 01/10/2020 21:24, Saravana Kannan wrote:
> > On Thu, Oct 1, 2020 at 5:56 AM Grygorii Strashko
> > <grygorii.strashko@ti.com> wrote:
> >>
> >>
> >>
> >> On 01/10/2020 11:22, Laurent Pinchart wrote:
> >>> Hi Tony,
> >>>
> >>> On Thu, Oct 01, 2020 at 11:17:48AM +0300, Tony Lindgren wrote:
> >>>> * Tony Lindgren <tony@atomide.com> [201001 07:53]:
> >>>>> * Peter Ujfalusi <peter.ujfalusi@ti.com> [200930 12:41]:
> >>>>>> Fwiw on my beagle x15
> >>>>>>
> >>>>>> v5.8
> >>>>>> [    9.908787] Run /sbin/init as init process
> >>>>>>
> >>>>>> v5.9-rc7
> >>>>>> [   15.085373] Run /sbin/init as init process
> >>>>>>
> >>>>>>
> >>>>>> It appears to be 'fixed' in next-20200928: the board does not even boot.
> >>>>>
> >>>>> Yeah so it seems :(
> >>>>>
> >>>>>> next-20200928 on omap5
> >>>>>> [    9.936806] Run /sbin/init as init process
> >>>>>>
> >>>>>>
> >>>>>> -rc7 spends most of it's time:
> >>>>>> [    7.635530] Micrel KSZ9031 Gigabit PHY 48485000.mdio:01: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=48485000.mdio:01, irq=POLL)
> >>>>>> [   14.956671] cpsw 48484000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off
> >>>>>> [   15.005211] IP-Config: Complete:
> >>>>>
> >>>>> Booting with initcall_debug I see this with current Linux next:
> >>>>>
> >>>>> ...
> >>>>> [    1.697313] cpuidle: using governor menu
> >>>>> [    1.701353] initcall init_menu+0x0/0xc returned 0 after 0 usecs
> >>>>> [    1.707458] calling  gpmc_init+0x0/0x10 @ 1
> >>>>> [    1.711784] initcall gpmc_init+0x0/0x10 returned 0 after 0 usecs
> >>>>> [    1.717974] calling  omap3_l3_init+0x0/0x10 @ 1
> >>>>> [    1.722653] initcall omap3_l3_init+0x0/0x10 returned 0 after 0 usecs
> >>>>> [    1.729201] calling  omap_l3_init+0x0/0x10 @ 1
> >>>>> [    1.733791] initcall omap_l3_init+0x0/0x10 returned 0 after 0 usecs
> >>>>> [    1.740314] calling  gate_vma_init+0x0/0x70 @ 1
> >>>>> [    1.744976] initcall gate_vma_init+0x0/0x70 returned 0 after 0 usecs
> >>>>> [    1.751522] calling  customize_machine+0x0/0x30 @ 1
> >>>>> [    3.823114] initcall customize_machine+0x0/0x30 returned 0 after 2011718 usecs
> >>>>> [    3.830566] calling  init_atags_procfs+0x0/0xec @ 1
> >>>>> [    3.835583] No ATAGs?
> >>>>
> >>>> And the long time above with customize_machine() ends up being
> >>>> pdata_quirks_init() calling of_platform_populate().
> >>>
> >>> That's what the delay is for me (I think I've reported that initially).
> >>>
> >>>>> Laurent & Tomi, care to check what you guys see in the slow booting case
> >>>>> after booting with initcall_debug?
> >>>>
> >>>> But maybe the long delay is something else for you guys so please check.
> >>>
> >>
> >> It's all devlink :( Looks like sometimes, improvements (PM) could became so complicated
> >> that time required to execute such algorithms may completely eliminate all expected benefits.
> >> Will not be surprised if PM consumption also increased instead of decreasing in some cases.
> >>
> >> not sure if it's 100% correct, but below diff reduces boot time
> >> from 7.6sec to 3.7sec :P
> >>
> >> before:
> >> [    0.053870] cpuidle: using governor menu
> >> [    2.505971] No ATAGs?
> >> ...
> >> [    7.562317] Freeing unused kernel memory: 1024K
> >>
> >> after:
> >> [    0.053800] cpuidle: using governor menu
> >> [    0.136853] No ATAGs?
> >> [    3.716218] devtmpfs: mounted
> >> [    3.719628] Freeing unused kernel memory: 1024K
> >> [    3.724266] Run /sbin/init as init process
> >>
> >> ----
> >> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> >> index 071f04da32c8..e0cc37ed46ca 100644
> >> --- a/drivers/of/platform.c
> >> +++ b/drivers/of/platform.c
> >> @@ -481,6 +481,7 @@ int of_platform_populate(struct device_node *root,
> >>           pr_debug(" starting at: %pOF\n", root);
> >>
> >>           device_links_supplier_sync_state_pause();
> >> +       fw_devlink_pause();
> >>           for_each_child_of_node(root, child) {
> >>                   rc = of_platform_bus_create(child, matches, lookup, parent, true);
> >>                   if (rc) {
> >> @@ -488,6 +489,7 @@ int of_platform_populate(struct device_node *root,
> >>                           break;
> >>                   }
> >>           }
> >> +       fw_devlink_resume();
> >>           device_links_supplier_sync_state_resume();
> >>
> >>           of_node_set_flag(root, OF_POPULATED_BUS);
> >> @@ -538,9 +540,7 @@ static int __init of_platform_default_populate_init(void)
> >>           }
> >>
> >>           /* Populate everything else. */
> >> -       fw_devlink_pause();
> >>           of_platform_default_populate(NULL, NULL, NULL);
> >> -       fw_devlink_resume();
> >
> > Your analysis is right, but this change is not safe. You'll get an
> > unlocked linked list trampling if you call it outside of where it's
> > called now. That's explicitly why I didn't do it the way this patch
> > does it.
> >
> > To explain more, if you call fw_devlink_pause/resume() inside
> > of_platform_populate() you can end up calling it in the context of
> > another device's probe function. When a device's probe function is
> > called, a has a bunch of other locks held and you'll cause a deadlock.
> > To avoid that, I had to use defer_fw_devlink_lock to manage the list
> > used by fw_devlink_pause/resume().
> >
> > I'll add more details later. But yeah, this patch isn't safe as is.
>
> I assume you going to fix it your way, right?

I'll be glad to fix this if I find a way out. But currently, there's
no "my way" for a generic fix to use inside of_platform_populate().
However...

> Just FYI. On ARM main DT population path is:
>
> arch_initcall(customize_machine)
>         machine_desc->init_machine();
>                 of_platform_default_populate();
>                 -- or --
>                 of_platform_populate();
>
> the of_platform_default_populate_init() called later due to make/linker dependencies.
>
> As result, existing pause/resume optimizations don't fully working.

We can just add this optimization around all the other places the top
level addition of DT devices is done. I wasn't aware of (more like
forgot) the init_machine() path.

Can you give the call path in your case? Just to make it a bit easier for me.

Thanks,
Saravana

Re: Slow booting on x15

[Saravana Kannan]

On Thu, Oct 1, 2020 at 3:22 PM Saravana Kannan <saravanak@google.com> wrote:
>
> On Thu, Oct 1, 2020 at 12:43 PM Grygorii Strashko
> <grygorii.strashko@ti.com> wrote:
> >
> >
> >
> > On 01/10/2020 21:24, Saravana Kannan wrote:
> > > On Thu, Oct 1, 2020 at 5:56 AM Grygorii Strashko
> > > <grygorii.strashko@ti.com> wrote:
> > >>
> > >>
> > >>
> > >> On 01/10/2020 11:22, Laurent Pinchart wrote:
> > >>> Hi Tony,
> > >>>
> > >>> On Thu, Oct 01, 2020 at 11:17:48AM +0300, Tony Lindgren wrote:
> > >>>> * Tony Lindgren <tony@atomide.com> [201001 07:53]:
> > >>>>> * Peter Ujfalusi <peter.ujfalusi@ti.com> [200930 12:41]:
> > >>>>>> Fwiw on my beagle x15
> > >>>>>>
> > >>>>>> v5.8
> > >>>>>> [    9.908787] Run /sbin/init as init process
> > >>>>>>
> > >>>>>> v5.9-rc7
> > >>>>>> [   15.085373] Run /sbin/init as init process
> > >>>>>>
> > >>>>>>
> > >>>>>> It appears to be 'fixed' in next-20200928: the board does not even boot.
> > >>>>>
> > >>>>> Yeah so it seems :(
> > >>>>>
> > >>>>>> next-20200928 on omap5
> > >>>>>> [    9.936806] Run /sbin/init as init process
> > >>>>>>
> > >>>>>>
> > >>>>>> -rc7 spends most of it's time:
> > >>>>>> [    7.635530] Micrel KSZ9031 Gigabit PHY 48485000.mdio:01: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=48485000.mdio:01, irq=POLL)
> > >>>>>> [   14.956671] cpsw 48484000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off
> > >>>>>> [   15.005211] IP-Config: Complete:
> > >>>>>
> > >>>>> Booting with initcall_debug I see this with current Linux next:
> > >>>>>
> > >>>>> ...
> > >>>>> [    1.697313] cpuidle: using governor menu
> > >>>>> [    1.701353] initcall init_menu+0x0/0xc returned 0 after 0 usecs
> > >>>>> [    1.707458] calling  gpmc_init+0x0/0x10 @ 1
> > >>>>> [    1.711784] initcall gpmc_init+0x0/0x10 returned 0 after 0 usecs
> > >>>>> [    1.717974] calling  omap3_l3_init+0x0/0x10 @ 1
> > >>>>> [    1.722653] initcall omap3_l3_init+0x0/0x10 returned 0 after 0 usecs
> > >>>>> [    1.729201] calling  omap_l3_init+0x0/0x10 @ 1
> > >>>>> [    1.733791] initcall omap_l3_init+0x0/0x10 returned 0 after 0 usecs
> > >>>>> [    1.740314] calling  gate_vma_init+0x0/0x70 @ 1
> > >>>>> [    1.744976] initcall gate_vma_init+0x0/0x70 returned 0 after 0 usecs
> > >>>>> [    1.751522] calling  customize_machine+0x0/0x30 @ 1
> > >>>>> [    3.823114] initcall customize_machine+0x0/0x30 returned 0 after 2011718 usecs
> > >>>>> [    3.830566] calling  init_atags_procfs+0x0/0xec @ 1
> > >>>>> [    3.835583] No ATAGs?
> > >>>>
> > >>>> And the long time above with customize_machine() ends up being
> > >>>> pdata_quirks_init() calling of_platform_populate().
> > >>>
> > >>> That's what the delay is for me (I think I've reported that initially).
> > >>>
> > >>>>> Laurent & Tomi, care to check what you guys see in the slow booting case
> > >>>>> after booting with initcall_debug?
> > >>>>
> > >>>> But maybe the long delay is something else for you guys so please check.
> > >>>
> > >>
> > >> It's all devlink :( Looks like sometimes, improvements (PM) could became so complicated
> > >> that time required to execute such algorithms may completely eliminate all expected benefits.
> > >> Will not be surprised if PM consumption also increased instead of decreasing in some cases.
> > >>
> > >> not sure if it's 100% correct, but below diff reduces boot time
> > >> from 7.6sec to 3.7sec :P
> > >>
> > >> before:
> > >> [    0.053870] cpuidle: using governor menu
> > >> [    2.505971] No ATAGs?
> > >> ...
> > >> [    7.562317] Freeing unused kernel memory: 1024K
> > >>
> > >> after:
> > >> [    0.053800] cpuidle: using governor menu
> > >> [    0.136853] No ATAGs?
> > >> [    3.716218] devtmpfs: mounted
> > >> [    3.719628] Freeing unused kernel memory: 1024K
> > >> [    3.724266] Run /sbin/init as init process
> > >>
> > >> ----
> > >> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > >> index 071f04da32c8..e0cc37ed46ca 100644
> > >> --- a/drivers/of/platform.c
> > >> +++ b/drivers/of/platform.c
> > >> @@ -481,6 +481,7 @@ int of_platform_populate(struct device_node *root,
> > >>           pr_debug(" starting at: %pOF\n", root);
> > >>
> > >>           device_links_supplier_sync_state_pause();
> > >> +       fw_devlink_pause();
> > >>           for_each_child_of_node(root, child) {
> > >>                   rc = of_platform_bus_create(child, matches, lookup, parent, true);
> > >>                   if (rc) {
> > >> @@ -488,6 +489,7 @@ int of_platform_populate(struct device_node *root,
> > >>                           break;
> > >>                   }
> > >>           }
> > >> +       fw_devlink_resume();
> > >>           device_links_supplier_sync_state_resume();
> > >>
> > >>           of_node_set_flag(root, OF_POPULATED_BUS);
> > >> @@ -538,9 +540,7 @@ static int __init of_platform_default_populate_init(void)
> > >>           }
> > >>
> > >>           /* Populate everything else. */
> > >> -       fw_devlink_pause();
> > >>           of_platform_default_populate(NULL, NULL, NULL);
> > >> -       fw_devlink_resume();
> > >
> > > Your analysis is right, but this change is not safe. You'll get an
> > > unlocked linked list trampling if you call it outside of where it's
> > > called now. That's explicitly why I didn't do it the way this patch
> > > does it.
> > >
> > > To explain more, if you call fw_devlink_pause/resume() inside
> > > of_platform_populate() you can end up calling it in the context of
> > > another device's probe function. When a device's probe function is
> > > called, a has a bunch of other locks held and you'll cause a deadlock.
> > > To avoid that, I had to use defer_fw_devlink_lock to manage the list
> > > used by fw_devlink_pause/resume().
> > >
> > > I'll add more details later. But yeah, this patch isn't safe as is.
> >
> > I assume you going to fix it your way, right?
>
> I'll be glad to fix this if I find a way out. But currently, there's
> no "my way" for a generic fix to use inside of_platform_populate().
> However...
>
> > Just FYI. On ARM main DT population path is:
> >
> > arch_initcall(customize_machine)
> >         machine_desc->init_machine();
> >                 of_platform_default_populate();
> >                 -- or --
> >                 of_platform_populate();
> >
> > the of_platform_default_populate_init() called later due to make/linker dependencies.
> >
> > As result, existing pause/resume optimizations don't fully working.
>
> We can just add this optimization around all the other places the top
> level addition of DT devices is done. I wasn't aware of (more like
> forgot) the init_machine() path.
>
> Can you give the call path in your case? Just to make it a bit easier for me.

I think I have a simple solution. I can just move the
fw_devlink_pause/resume() inside of_platform_default_populate() and
call those only if "root" == NULL.

-Saravana

Re: Slow booting on x15

[Laurent Pinchart]

Hi Saravana,

On Thu, Oct 01, 2020 at 03:30:39PM -0700, Saravana Kannan wrote:
> On Thu, Oct 1, 2020 at 3:22 PM Saravana Kannan wrote:
> > On Thu, Oct 1, 2020 at 12:43 PM Grygorii Strashko wrote:
> > > On 01/10/2020 21:24, Saravana Kannan wrote:
> > > > On Thu, Oct 1, 2020 at 5:56 AM Grygorii Strashko wrote:
> > > >> On 01/10/2020 11:22, Laurent Pinchart wrote:
> > > >>> On Thu, Oct 01, 2020 at 11:17:48AM +0300, Tony Lindgren wrote:
> > > >>>> * Tony Lindgren <tony@atomide.com> [201001 07:53]:
> > > >>>>> * Peter Ujfalusi <peter.ujfalusi@ti.com> [200930 12:41]:
> > > >>>>>> Fwiw on my beagle x15
> > > >>>>>>
> > > >>>>>> v5.8
> > > >>>>>> [    9.908787] Run /sbin/init as init process
> > > >>>>>>
> > > >>>>>> v5.9-rc7
> > > >>>>>> [   15.085373] Run /sbin/init as init process
> > > >>>>>>
> > > >>>>>>
> > > >>>>>> It appears to be 'fixed' in next-20200928: the board does not even boot.
> > > >>>>>
> > > >>>>> Yeah so it seems :(
> > > >>>>>
> > > >>>>>> next-20200928 on omap5
> > > >>>>>> [    9.936806] Run /sbin/init as init process
> > > >>>>>>
> > > >>>>>>
> > > >>>>>> -rc7 spends most of it's time:
> > > >>>>>> [    7.635530] Micrel KSZ9031 Gigabit PHY 48485000.mdio:01: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=48485000.mdio:01, irq=POLL)
> > > >>>>>> [   14.956671] cpsw 48484000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off
> > > >>>>>> [   15.005211] IP-Config: Complete:
> > > >>>>>
> > > >>>>> Booting with initcall_debug I see this with current Linux next:
> > > >>>>>
> > > >>>>> ...
> > > >>>>> [    1.697313] cpuidle: using governor menu
> > > >>>>> [    1.701353] initcall init_menu+0x0/0xc returned 0 after 0 usecs
> > > >>>>> [    1.707458] calling  gpmc_init+0x0/0x10 @ 1
> > > >>>>> [    1.711784] initcall gpmc_init+0x0/0x10 returned 0 after 0 usecs
> > > >>>>> [    1.717974] calling  omap3_l3_init+0x0/0x10 @ 1
> > > >>>>> [    1.722653] initcall omap3_l3_init+0x0/0x10 returned 0 after 0 usecs
> > > >>>>> [    1.729201] calling  omap_l3_init+0x0/0x10 @ 1
> > > >>>>> [    1.733791] initcall omap_l3_init+0x0/0x10 returned 0 after 0 usecs
> > > >>>>> [    1.740314] calling  gate_vma_init+0x0/0x70 @ 1
> > > >>>>> [    1.744976] initcall gate_vma_init+0x0/0x70 returned 0 after 0 usecs
> > > >>>>> [    1.751522] calling  customize_machine+0x0/0x30 @ 1
> > > >>>>> [    3.823114] initcall customize_machine+0x0/0x30 returned 0 after 2011718 usecs
> > > >>>>> [    3.830566] calling  init_atags_procfs+0x0/0xec @ 1
> > > >>>>> [    3.835583] No ATAGs?
> > > >>>>
> > > >>>> And the long time above with customize_machine() ends up being
> > > >>>> pdata_quirks_init() calling of_platform_populate().
> > > >>>
> > > >>> That's what the delay is for me (I think I've reported that initially).
> > > >>>
> > > >>>>> Laurent & Tomi, care to check what you guys see in the slow booting case
> > > >>>>> after booting with initcall_debug?
> > > >>>>
> > > >>>> But maybe the long delay is something else for you guys so please check.
> > > >>>
> > > >>
> > > >> It's all devlink :( Looks like sometimes, improvements (PM) could became so complicated
> > > >> that time required to execute such algorithms may completely eliminate all expected benefits.
> > > >> Will not be surprised if PM consumption also increased instead of decreasing in some cases.
> > > >>
> > > >> not sure if it's 100% correct, but below diff reduces boot time
> > > >> from 7.6sec to 3.7sec :P
> > > >>
> > > >> before:
> > > >> [    0.053870] cpuidle: using governor menu
> > > >> [    2.505971] No ATAGs?
> > > >> ...
> > > >> [    7.562317] Freeing unused kernel memory: 1024K
> > > >>
> > > >> after:
> > > >> [    0.053800] cpuidle: using governor menu
> > > >> [    0.136853] No ATAGs?
> > > >> [    3.716218] devtmpfs: mounted
> > > >> [    3.719628] Freeing unused kernel memory: 1024K
> > > >> [    3.724266] Run /sbin/init as init process
> > > >>
> > > >> ----
> > > >> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > > >> index 071f04da32c8..e0cc37ed46ca 100644
> > > >> --- a/drivers/of/platform.c
> > > >> +++ b/drivers/of/platform.c
> > > >> @@ -481,6 +481,7 @@ int of_platform_populate(struct device_node *root,
> > > >>           pr_debug(" starting at: %pOF\n", root);
> > > >>
> > > >>           device_links_supplier_sync_state_pause();
> > > >> +       fw_devlink_pause();
> > > >>           for_each_child_of_node(root, child) {
> > > >>                   rc = of_platform_bus_create(child, matches, lookup, parent, true);
> > > >>                   if (rc) {
> > > >> @@ -488,6 +489,7 @@ int of_platform_populate(struct device_node *root,
> > > >>                           break;
> > > >>                   }
> > > >>           }
> > > >> +       fw_devlink_resume();
> > > >>           device_links_supplier_sync_state_resume();
> > > >>
> > > >>           of_node_set_flag(root, OF_POPULATED_BUS);
> > > >> @@ -538,9 +540,7 @@ static int __init of_platform_default_populate_init(void)
> > > >>           }
> > > >>
> > > >>           /* Populate everything else. */
> > > >> -       fw_devlink_pause();
> > > >>           of_platform_default_populate(NULL, NULL, NULL);
> > > >> -       fw_devlink_resume();
> > > >
> > > > Your analysis is right, but this change is not safe. You'll get an
> > > > unlocked linked list trampling if you call it outside of where it's
> > > > called now. That's explicitly why I didn't do it the way this patch
> > > > does it.
> > > >
> > > > To explain more, if you call fw_devlink_pause/resume() inside
> > > > of_platform_populate() you can end up calling it in the context of
> > > > another device's probe function. When a device's probe function is
> > > > called, a has a bunch of other locks held and you'll cause a deadlock.
> > > > To avoid that, I had to use defer_fw_devlink_lock to manage the list
> > > > used by fw_devlink_pause/resume().
> > > >
> > > > I'll add more details later. But yeah, this patch isn't safe as is.
> > >
> > > I assume you going to fix it your way, right?
> >
> > I'll be glad to fix this if I find a way out. But currently, there's
> > no "my way" for a generic fix to use inside of_platform_populate().
> > However...
> >
> > > Just FYI. On ARM main DT population path is:
> > >
> > > arch_initcall(customize_machine)
> > >         machine_desc->init_machine();
> > >                 of_platform_default_populate();
> > >                 -- or --
> > >                 of_platform_populate();
> > >
> > > the of_platform_default_populate_init() called later due to make/linker dependencies.
> > >
> > > As result, existing pause/resume optimizations don't fully working.
> >
> > We can just add this optimization around all the other places the top
> > level addition of DT devices is done. I wasn't aware of (more like
> > forgot) the init_machine() path.
> >
> > Can you give the call path in your case? Just to make it a bit easier for me.
> 
> I think I have a simple solution. I can just move the
> fw_devlink_pause/resume() inside of_platform_default_populate() and
> call those only if "root" == NULL.

I'd be happy to test a patch. On my device, the initial
of_platform_populate() call from machine_desc->init_machine() takes
between 6 and 10 seconds to run with v5.9-rc5, compared to 200ms on
v5.7. That's a fairly bad regression, all the people who have worked
hard so reduce boot time would really hate this :-)

-- 
Regards,

Laurent Pinchart

Re: Slow booting on x15

[Saravana Kannan]

On Thu, Oct 1, 2020 at 3:39 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Saravana,
>
> On Thu, Oct 01, 2020 at 03:30:39PM -0700, Saravana Kannan wrote:
> > On Thu, Oct 1, 2020 at 3:22 PM Saravana Kannan wrote:
> > > On Thu, Oct 1, 2020 at 12:43 PM Grygorii Strashko wrote:
> > > > On 01/10/2020 21:24, Saravana Kannan wrote:
> > > > > On Thu, Oct 1, 2020 at 5:56 AM Grygorii Strashko wrote:
> > > > >> On 01/10/2020 11:22, Laurent Pinchart wrote:
> > > > >>> On Thu, Oct 01, 2020 at 11:17:48AM +0300, Tony Lindgren wrote:
> > > > >>>> * Tony Lindgren <tony@atomide.com> [201001 07:53]:
> > > > >>>>> * Peter Ujfalusi <peter.ujfalusi@ti.com> [200930 12:41]:
> > > > >>>>>> Fwiw on my beagle x15
> > > > >>>>>>
> > > > >>>>>> v5.8
> > > > >>>>>> [    9.908787] Run /sbin/init as init process
> > > > >>>>>>
> > > > >>>>>> v5.9-rc7
> > > > >>>>>> [   15.085373] Run /sbin/init as init process
> > > > >>>>>>
> > > > >>>>>>
> > > > >>>>>> It appears to be 'fixed' in next-20200928: the board does not even boot.
> > > > >>>>>
> > > > >>>>> Yeah so it seems :(
> > > > >>>>>
> > > > >>>>>> next-20200928 on omap5
> > > > >>>>>> [    9.936806] Run /sbin/init as init process
> > > > >>>>>>
> > > > >>>>>>
> > > > >>>>>> -rc7 spends most of it's time:
> > > > >>>>>> [    7.635530] Micrel KSZ9031 Gigabit PHY 48485000.mdio:01: attached PHY driver [Micrel KSZ9031 Gigabit PHY] (mii_bus:phy_addr=48485000.mdio:01, irq=POLL)
> > > > >>>>>> [   14.956671] cpsw 48484000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off
> > > > >>>>>> [   15.005211] IP-Config: Complete:
> > > > >>>>>
> > > > >>>>> Booting with initcall_debug I see this with current Linux next:
> > > > >>>>>
> > > > >>>>> ...
> > > > >>>>> [    1.697313] cpuidle: using governor menu
> > > > >>>>> [    1.701353] initcall init_menu+0x0/0xc returned 0 after 0 usecs
> > > > >>>>> [    1.707458] calling  gpmc_init+0x0/0x10 @ 1
> > > > >>>>> [    1.711784] initcall gpmc_init+0x0/0x10 returned 0 after 0 usecs
> > > > >>>>> [    1.717974] calling  omap3_l3_init+0x0/0x10 @ 1
> > > > >>>>> [    1.722653] initcall omap3_l3_init+0x0/0x10 returned 0 after 0 usecs
> > > > >>>>> [    1.729201] calling  omap_l3_init+0x0/0x10 @ 1
> > > > >>>>> [    1.733791] initcall omap_l3_init+0x0/0x10 returned 0 after 0 usecs
> > > > >>>>> [    1.740314] calling  gate_vma_init+0x0/0x70 @ 1
> > > > >>>>> [    1.744976] initcall gate_vma_init+0x0/0x70 returned 0 after 0 usecs
> > > > >>>>> [    1.751522] calling  customize_machine+0x0/0x30 @ 1
> > > > >>>>> [    3.823114] initcall customize_machine+0x0/0x30 returned 0 after 2011718 usecs
> > > > >>>>> [    3.830566] calling  init_atags_procfs+0x0/0xec @ 1
> > > > >>>>> [    3.835583] No ATAGs?
> > > > >>>>
> > > > >>>> And the long time above with customize_machine() ends up being
> > > > >>>> pdata_quirks_init() calling of_platform_populate().
> > > > >>>
> > > > >>> That's what the delay is for me (I think I've reported that initially).
> > > > >>>
> > > > >>>>> Laurent & Tomi, care to check what you guys see in the slow booting case
> > > > >>>>> after booting with initcall_debug?
> > > > >>>>
> > > > >>>> But maybe the long delay is something else for you guys so please check.
> > > > >>>
> > > > >>
> > > > >> It's all devlink :( Looks like sometimes, improvements (PM) could became so complicated
> > > > >> that time required to execute such algorithms may completely eliminate all expected benefits.
> > > > >> Will not be surprised if PM consumption also increased instead of decreasing in some cases.
> > > > >>
> > > > >> not sure if it's 100% correct, but below diff reduces boot time
> > > > >> from 7.6sec to 3.7sec :P
> > > > >>
> > > > >> before:
> > > > >> [    0.053870] cpuidle: using governor menu
> > > > >> [    2.505971] No ATAGs?
> > > > >> ...
> > > > >> [    7.562317] Freeing unused kernel memory: 1024K
> > > > >>
> > > > >> after:
> > > > >> [    0.053800] cpuidle: using governor menu
> > > > >> [    0.136853] No ATAGs?
> > > > >> [    3.716218] devtmpfs: mounted
> > > > >> [    3.719628] Freeing unused kernel memory: 1024K
> > > > >> [    3.724266] Run /sbin/init as init process
> > > > >>
> > > > >> ----
> > > > >> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > > > >> index 071f04da32c8..e0cc37ed46ca 100644
> > > > >> --- a/drivers/of/platform.c
> > > > >> +++ b/drivers/of/platform.c
> > > > >> @@ -481,6 +481,7 @@ int of_platform_populate(struct device_node *root,
> > > > >>           pr_debug(" starting at: %pOF\n", root);
> > > > >>
> > > > >>           device_links_supplier_sync_state_pause();
> > > > >> +       fw_devlink_pause();
> > > > >>           for_each_child_of_node(root, child) {
> > > > >>                   rc = of_platform_bus_create(child, matches, lookup, parent, true);
> > > > >>                   if (rc) {
> > > > >> @@ -488,6 +489,7 @@ int of_platform_populate(struct device_node *root,
> > > > >>                           break;
> > > > >>                   }
> > > > >>           }
> > > > >> +       fw_devlink_resume();
> > > > >>           device_links_supplier_sync_state_resume();
> > > > >>
> > > > >>           of_node_set_flag(root, OF_POPULATED_BUS);
> > > > >> @@ -538,9 +540,7 @@ static int __init of_platform_default_populate_init(void)
> > > > >>           }
> > > > >>
> > > > >>           /* Populate everything else. */
> > > > >> -       fw_devlink_pause();
> > > > >>           of_platform_default_populate(NULL, NULL, NULL);
> > > > >> -       fw_devlink_resume();
> > > > >
> > > > > Your analysis is right, but this change is not safe. You'll get an
> > > > > unlocked linked list trampling if you call it outside of where it's
> > > > > called now. That's explicitly why I didn't do it the way this patch
> > > > > does it.
> > > > >
> > > > > To explain more, if you call fw_devlink_pause/resume() inside
> > > > > of_platform_populate() you can end up calling it in the context of
> > > > > another device's probe function. When a device's probe function is
> > > > > called, a has a bunch of other locks held and you'll cause a deadlock.
> > > > > To avoid that, I had to use defer_fw_devlink_lock to manage the list
> > > > > used by fw_devlink_pause/resume().
> > > > >
> > > > > I'll add more details later. But yeah, this patch isn't safe as is.
> > > >
> > > > I assume you going to fix it your way, right?
> > >
> > > I'll be glad to fix this if I find a way out. But currently, there's
> > > no "my way" for a generic fix to use inside of_platform_populate().
> > > However...
> > >
> > > > Just FYI. On ARM main DT population path is:
> > > >
> > > > arch_initcall(customize_machine)
> > > >         machine_desc->init_machine();
> > > >                 of_platform_default_populate();
> > > >                 -- or --
> > > >                 of_platform_populate();
> > > >
> > > > the of_platform_default_populate_init() called later due to make/linker dependencies.
> > > >
> > > > As result, existing pause/resume optimizations don't fully working.
> > >
> > > We can just add this optimization around all the other places the top
> > > level addition of DT devices is done. I wasn't aware of (more like
> > > forgot) the init_machine() path.
> > >
> > > Can you give the call path in your case? Just to make it a bit easier for me.
> >
> > I think I have a simple solution. I can just move the
> > fw_devlink_pause/resume() inside of_platform_default_populate() and
> > call those only if "root" == NULL.
>
> I'd be happy to test a patch. On my device, the initial
> of_platform_populate() call from machine_desc->init_machine() takes
> between 6 and 10 seconds to run with v5.9-rc5, compared to 200ms on
> v5.7. That's a fairly bad regression, all the people who have worked
> hard so reduce boot time would really hate this :-)

Thanks! Patch coming up in a few minutes.

-Saravana

[PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Saravana Kannan]

When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
adding all top level devices") optimized the fwnode parsing when all top
level devices are added, it missed out optimizing this for platform
where the top level devices are added through the init_machine() path.

This commit does the optimization for all paths by simply moving the
fw_devlink_pause/resume() inside of_platform_default_populate().

Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
---
 drivers/of/platform.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 071f04da32c8..79972e49b539 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
 				 const struct of_dev_auxdata *lookup,
 				 struct device *parent)
 {
-	return of_platform_populate(root, of_default_bus_match_table, lookup,
-				    parent);
+	int ret;
+
+	/*
+	 * fw_devlink_pause/resume() are only safe to be called around top
+	 * level device addition due to locking constraints.
+	 */
+	if (!root)
+		fw_devlink_pause();
+
+	ret = of_platform_populate(root, of_default_bus_match_table, lookup,
+				   parent);
+
+	if (!root)
+		fw_devlink_resume();
+	return ret;
 }
 EXPORT_SYMBOL_GPL(of_platform_default_populate);
 
@@ -538,9 +551,7 @@ static int __init of_platform_default_populate_init(void)
 	}
 
 	/* Populate everything else. */
-	fw_devlink_pause();
 	of_platform_default_populate(NULL, NULL, NULL);
-	fw_devlink_resume();
 
 	return 0;
 }
-- 
2.28.0.709.gb0816b6eb0-goog

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Laurent Pinchart]

Hi Saravana,

Thank you for the patch.

On Thu, Oct 01, 2020 at 03:59:51PM -0700, Saravana Kannan wrote:
> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> adding all top level devices") optimized the fwnode parsing when all top
> level devices are added, it missed out optimizing this for platform
> where the top level devices are added through the init_machine() path.
> 
> This commit does the optimization for all paths by simply moving the
> fw_devlink_pause/resume() inside of_platform_default_populate().

Based on v5.9-rc5, before the patch:

[    0.652887] cpuidle: using governor menu
[   12.349476] No ATAGs?

After the patch:

[    0.650460] cpuidle: using governor menu
[   12.262101] No ATAGs?

:-(

> Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> Signed-off-by: Saravana Kannan <saravanak@google.com>
> ---
>  drivers/of/platform.c | 19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 071f04da32c8..79972e49b539 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
>  				 const struct of_dev_auxdata *lookup,
>  				 struct device *parent)
>  {
> -	return of_platform_populate(root, of_default_bus_match_table, lookup,
> -				    parent);
> +	int ret;
> +
> +	/*
> +	 * fw_devlink_pause/resume() are only safe to be called around top
> +	 * level device addition due to locking constraints.
> +	 */
> +	if (!root)
> +		fw_devlink_pause();
> +
> +	ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> +				   parent);
> +
> +	if (!root)
> +		fw_devlink_resume();
> +	return ret;
>  }
>  EXPORT_SYMBOL_GPL(of_platform_default_populate);
>  
> @@ -538,9 +551,7 @@ static int __init of_platform_default_populate_init(void)
>  	}
>  
>  	/* Populate everything else. */
> -	fw_devlink_pause();
>  	of_platform_default_populate(NULL, NULL, NULL);
> -	fw_devlink_resume();
>  
>  	return 0;
>  }

-- 
Regards,

Laurent Pinchart

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Grygorii Strashko]

On 02/10/2020 02:19, Laurent Pinchart wrote:
> Hi Saravana,
> 
> Thank you for the patch.
> 
> On Thu, Oct 01, 2020 at 03:59:51PM -0700, Saravana Kannan wrote:
>> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
>> adding all top level devices") optimized the fwnode parsing when all top
>> level devices are added, it missed out optimizing this for platform
>> where the top level devices are added through the init_machine() path.
>>
>> This commit does the optimization for all paths by simply moving the
>> fw_devlink_pause/resume() inside of_platform_default_populate().
> 
> Based on v5.9-rc5, before the patch:
> 
> [    0.652887] cpuidle: using governor menu
> [   12.349476] No ATAGs?
> 
> After the patch:
> 
> [    0.650460] cpuidle: using governor menu
> [   12.262101] No ATAGs?
> 
> :-(

This is kinda expected :( because omap2 arch doesn't call of_platform_default_populate()

Call path:
board-generic.c
  DT_MACHINE_START()
    .init_machine	= omap_generic_init,

  omap_generic_init()
    pdata_quirks_init(omap_dt_match_table);
		of_platform_populate(NULL, omap_dt_match_table,
			     omap_auxdata_lookup, NULL);

Other affected platforms
arm: mach-ux500
some mips
some powerpc

there are also case when a lot of devices placed under bus node, in such case
  of_platform_populate() calls from bus drivers will also suffer from this issue.

I think one option could be to add some parameter to _populate() or introduce new api.

By the way, is there option to disable this feature at all?
Is there Kconfig option?
Is there any reasons why such complex and time consuming code added to the kernel and not implemented on DTC level?


Also, I've came with another diff, pls check.

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 5.9.0-rc6-01791-g9acba6b38757-dirty (grygorii@grygorii-XPS-13-9370) (arm-linux-gnueabihf-gcc (GNU Toolcha0
[    0.000000] CPU: ARMv7 Processor [412fc0f2] revision 2 (ARMv7), cr=10c5387d
[    0.000000] CPU: div instructions available: patching division code
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
[    0.000000] OF: fdt: Machine model: TI AM5718 IDK
...
[    0.053443] cpuidle: using governor ladder
[    0.053470] cpuidle: using governor menu
[    0.089304] No ATAGs?
...
[    3.092291] devtmpfs: mounted
[    3.095804] Freeing unused kernel memory: 1024K
[    3.100483] Run /sbin/init as init process



------ >< ---
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 071f04da32c8..4521b26e7745 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -514,6 +514,12 @@ static const struct of_device_id reserved_mem_matches[] = {
         {}
  };
  
+static int __init of_platform_fw_devlink_pause(void)
+{
+       fw_devlink_pause();
+}
+core_initcall(of_platform_fw_devlink_pause);
+
  static int __init of_platform_default_populate_init(void)
  {
         struct device_node *node;
@@ -538,9 +544,7 @@ static int __init of_platform_default_populate_init(void)
         }
  
         /* Populate everything else. */
-       fw_devlink_pause();
         of_platform_default_populate(NULL, NULL, NULL);
-       fw_devlink_resume();
  
         return 0;
  }
@@ -548,6 +552,7 @@ arch_initcall_sync(of_platform_default_populate_init);
  
  static int __init of_platform_sync_state_init(void)
  {
+       fw_devlink_resume();
         device_links_supplier_sync_state_resume();
         return 0;
  }



-- 
Best regards,
grygorii

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Grygorii Strashko]

On 02/10/2020 14:40, Grygorii Strashko wrote:
> 
> 
> On 02/10/2020 02:19, Laurent Pinchart wrote:
>> Hi Saravana,
>>
>> Thank you for the patch.
>>
>> On Thu, Oct 01, 2020 at 03:59:51PM -0700, Saravana Kannan wrote:
>>> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
>>> adding all top level devices") optimized the fwnode parsing when all top
>>> level devices are added, it missed out optimizing this for platform
>>> where the top level devices are added through the init_machine() path.
>>>
>>> This commit does the optimization for all paths by simply moving the
>>> fw_devlink_pause/resume() inside of_platform_default_populate().
>>
>> Based on v5.9-rc5, before the patch:
>>
>> [    0.652887] cpuidle: using governor menu
>> [   12.349476] No ATAGs?
>>
>> After the patch:
>>
>> [    0.650460] cpuidle: using governor menu
>> [   12.262101] No ATAGs?
>>
>> :-(
> 
> This is kinda expected :( because omap2 arch doesn't call of_platform_default_populate()
> 
> Call path:
> board-generic.c
>   DT_MACHINE_START()
>     .init_machine    = omap_generic_init,
> 
>   omap_generic_init()
>     pdata_quirks_init(omap_dt_match_table);
>          of_platform_populate(NULL, omap_dt_match_table,
>                   omap_auxdata_lookup, NULL);
> 
> Other affected platforms
> arm: mach-ux500
> some mips
> some powerpc
> 
> there are also case when a lot of devices placed under bus node, in such case
>   of_platform_populate() calls from bus drivers will also suffer from this issue.
> 
> I think one option could be to add some parameter to _populate() or introduce new api.
> 
> By the way, is there option to disable this feature at all?
> Is there Kconfig option?
> Is there any reasons why such complex and time consuming code added to the kernel and not implemented on DTC level?
> 
> 
> Also, I've came with another diff, pls check.
> 
> [    0.000000] Booting Linux on physical CPU 0x0
> [    0.000000] Linux version 5.9.0-rc6-01791-g9acba6b38757-dirty (grygorii@grygorii-XPS-13-9370) (arm-linux-gnueabihf-gcc (GNU Toolcha0
> [    0.000000] CPU: ARMv7 Processor [412fc0f2] revision 2 (ARMv7), cr=10c5387d
> [    0.000000] CPU: div instructions available: patching division code
> [    0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
> [    0.000000] OF: fdt: Machine model: TI AM5718 IDK
> ...
> [    0.053443] cpuidle: using governor ladder
> [    0.053470] cpuidle: using governor menu
> [    0.089304] No ATAGs?
> ...
> [    3.092291] devtmpfs: mounted
> [    3.095804] Freeing unused kernel memory: 1024K
> [    3.100483] Run /sbin/init as init process
> 
> 
> 
> ------ >< ---
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 071f04da32c8..4521b26e7745 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -514,6 +514,12 @@ static const struct of_device_id reserved_mem_matches[] = {
>          {}
>   };
> 
> +static int __init of_platform_fw_devlink_pause(void)
> +{
> +       fw_devlink_pause();
> +}
> +core_initcall(of_platform_fw_devlink_pause);
> +
>   static int __init of_platform_default_populate_init(void)
>   {
>          struct device_node *node;
> @@ -538,9 +544,7 @@ static int __init of_platform_default_populate_init(void)
>          }
> 
>          /* Populate everything else. */
> -       fw_devlink_pause();
>          of_platform_default_populate(NULL, NULL, NULL);
> -       fw_devlink_resume();
> 
>          return 0;
>   }
> @@ -548,6 +552,7 @@ arch_initcall_sync(of_platform_default_populate_init);
> 
>   static int __init of_platform_sync_state_init(void)
>   {
> +       fw_devlink_resume();

^ it seems has to be done earlier, like
+static int __init of_platform_fw_devlink_resume(void)
+{
+       fw_devlink_resume();
+       return 0;
+}
+device_initcall_sync(of_platform_fw_devlink_resume);


>          device_links_supplier_sync_state_resume();
>          return 0;
>   }
> 
> 
> 

-- 
Best regards,
grygorii

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Saravana Kannan]

On Fri, Oct 2, 2020 at 8:03 AM 'Grygorii Strashko' via kernel-team
<kernel-team@android.com> wrote:
>
>
>
> On 02/10/2020 14:40, Grygorii Strashko wrote:
> >
> >
> > On 02/10/2020 02:19, Laurent Pinchart wrote:
> >> Hi Saravana,
> >>
> >> Thank you for the patch.
> >>
> >> On Thu, Oct 01, 2020 at 03:59:51PM -0700, Saravana Kannan wrote:
> >>> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> >>> adding all top level devices") optimized the fwnode parsing when all top
> >>> level devices are added, it missed out optimizing this for platform
> >>> where the top level devices are added through the init_machine() path.
> >>>
> >>> This commit does the optimization for all paths by simply moving the
> >>> fw_devlink_pause/resume() inside of_platform_default_populate().
> >>
> >> Based on v5.9-rc5, before the patch:
> >>
> >> [    0.652887] cpuidle: using governor menu
> >> [   12.349476] No ATAGs?
> >>
> >> After the patch:
> >>
> >> [    0.650460] cpuidle: using governor menu
> >> [   12.262101] No ATAGs?
> >>
> >> :-(
> >
> > This is kinda expected :( because omap2 arch doesn't call of_platform_default_populate()
> >
> > Call path:
> > board-generic.c
> >   DT_MACHINE_START()
> >     .init_machine    = omap_generic_init,
> >
> >   omap_generic_init()
> >     pdata_quirks_init(omap_dt_match_table);
> >          of_platform_populate(NULL, omap_dt_match_table,
> >                   omap_auxdata_lookup, NULL);
> >
> > Other affected platforms
> > arm: mach-ux500
> > some mips
> > some powerpc
> >
> > there are also case when a lot of devices placed under bus node, in such case
> >   of_platform_populate() calls from bus drivers will also suffer from this issue.
> >
> > I think one option could be to add some parameter to _populate() or introduce new api.
> >
> > By the way, is there option to disable this feature at all?
> > Is there Kconfig option?
> > Is there any reasons why such complex and time consuming code added to the kernel and not implemented on DTC level?
> >
> >
> > Also, I've came with another diff, pls check.
> >
> > [    0.000000] Booting Linux on physical CPU 0x0
> > [    0.000000] Linux version 5.9.0-rc6-01791-g9acba6b38757-dirty (grygorii@grygorii-XPS-13-9370) (arm-linux-gnueabihf-gcc (GNU Toolcha0
> > [    0.000000] CPU: ARMv7 Processor [412fc0f2] revision 2 (ARMv7), cr=10c5387d
> > [    0.000000] CPU: div instructions available: patching division code
> > [    0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
> > [    0.000000] OF: fdt: Machine model: TI AM5718 IDK
> > ...
> > [    0.053443] cpuidle: using governor ladder
> > [    0.053470] cpuidle: using governor menu
> > [    0.089304] No ATAGs?
> > ...
> > [    3.092291] devtmpfs: mounted
> > [    3.095804] Freeing unused kernel memory: 1024K
> > [    3.100483] Run /sbin/init as init process
> >
> >
> >
> > ------ >< ---
> > diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > index 071f04da32c8..4521b26e7745 100644
> > --- a/drivers/of/platform.c
> > +++ b/drivers/of/platform.c
> > @@ -514,6 +514,12 @@ static const struct of_device_id reserved_mem_matches[] = {
> >          {}
> >   };
> >
> > +static int __init of_platform_fw_devlink_pause(void)
> > +{
> > +       fw_devlink_pause();
> > +}
> > +core_initcall(of_platform_fw_devlink_pause);
> > +
> >   static int __init of_platform_default_populate_init(void)
> >   {
> >          struct device_node *node;
> > @@ -538,9 +544,7 @@ static int __init of_platform_default_populate_init(void)
> >          }
> >
> >          /* Populate everything else. */
> > -       fw_devlink_pause();
> >          of_platform_default_populate(NULL, NULL, NULL);
> > -       fw_devlink_resume();
> >
> >          return 0;
> >   }
> > @@ -548,6 +552,7 @@ arch_initcall_sync(of_platform_default_populate_init);
> >
> >   static int __init of_platform_sync_state_init(void)
> >   {
> > +       fw_devlink_resume();
>
> ^ it seems has to be done earlier, like
> +static int __init of_platform_fw_devlink_resume(void)
> +{
> +       fw_devlink_resume();
> +       return 0;
> +}
> +device_initcall_sync(of_platform_fw_devlink_resume);

This will mean no device will probe until device_initcall_sync().
Unfortunately, I don't think we can make such a sweeping assumption.

-Saravana

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Grygorii Strashko]

On 02/10/2020 20:48, Saravana Kannan wrote:
> On Fri, Oct 2, 2020 at 8:03 AM 'Grygorii Strashko' via kernel-team
> <kernel-team@android.com> wrote:
>>
>>
>>
>> On 02/10/2020 14:40, Grygorii Strashko wrote:
>>>
>>>
>>> On 02/10/2020 02:19, Laurent Pinchart wrote:
>>>> Hi Saravana,
>>>>
>>>> Thank you for the patch.
>>>>
>>>> On Thu, Oct 01, 2020 at 03:59:51PM -0700, Saravana Kannan wrote:
>>>>> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
>>>>> adding all top level devices") optimized the fwnode parsing when all top
>>>>> level devices are added, it missed out optimizing this for platform
>>>>> where the top level devices are added through the init_machine() path.
>>>>>
>>>>> This commit does the optimization for all paths by simply moving the
>>>>> fw_devlink_pause/resume() inside of_platform_default_populate().
>>>>
>>>> Based on v5.9-rc5, before the patch:
>>>>
>>>> [    0.652887] cpuidle: using governor menu
>>>> [   12.349476] No ATAGs?
>>>>
>>>> After the patch:
>>>>
>>>> [    0.650460] cpuidle: using governor menu
>>>> [   12.262101] No ATAGs?
>>>>
>>>> :-(
>>>
>>> This is kinda expected :( because omap2 arch doesn't call of_platform_default_populate()
>>>
>>> Call path:
>>> board-generic.c
>>>    DT_MACHINE_START()
>>>      .init_machine    = omap_generic_init,
>>>
>>>    omap_generic_init()
>>>      pdata_quirks_init(omap_dt_match_table);
>>>           of_platform_populate(NULL, omap_dt_match_table,
>>>                    omap_auxdata_lookup, NULL);
>>>
>>> Other affected platforms
>>> arm: mach-ux500
>>> some mips
>>> some powerpc
>>>
>>> there are also case when a lot of devices placed under bus node, in such case
>>>    of_platform_populate() calls from bus drivers will also suffer from this issue.
>>>
>>> I think one option could be to add some parameter to _populate() or introduce new api.
>>>
>>> By the way, is there option to disable this feature at all?
>>> Is there Kconfig option?
>>> Is there any reasons why such complex and time consuming code added to the kernel and not implemented on DTC level?
>>>
>>>
>>> Also, I've came with another diff, pls check.
>>>
>>> [    0.000000] Booting Linux on physical CPU 0x0
>>> [    0.000000] Linux version 5.9.0-rc6-01791-g9acba6b38757-dirty (grygorii@grygorii-XPS-13-9370) (arm-linux-gnueabihf-gcc (GNU Toolcha0
>>> [    0.000000] CPU: ARMv7 Processor [412fc0f2] revision 2 (ARMv7), cr=10c5387d
>>> [    0.000000] CPU: div instructions available: patching division code
>>> [    0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
>>> [    0.000000] OF: fdt: Machine model: TI AM5718 IDK
>>> ...
>>> [    0.053443] cpuidle: using governor ladder
>>> [    0.053470] cpuidle: using governor menu
>>> [    0.089304] No ATAGs?
>>> ...
>>> [    3.092291] devtmpfs: mounted
>>> [    3.095804] Freeing unused kernel memory: 1024K
>>> [    3.100483] Run /sbin/init as init process
>>>
>>>
>>>
>>> ------ >< ---
>>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
>>> index 071f04da32c8..4521b26e7745 100644
>>> --- a/drivers/of/platform.c
>>> +++ b/drivers/of/platform.c
>>> @@ -514,6 +514,12 @@ static const struct of_device_id reserved_mem_matches[] = {
>>>           {}
>>>    };
>>>
>>> +static int __init of_platform_fw_devlink_pause(void)
>>> +{
>>> +       fw_devlink_pause();
>>> +}
>>> +core_initcall(of_platform_fw_devlink_pause);
>>> +
>>>    static int __init of_platform_default_populate_init(void)
>>>    {
>>>           struct device_node *node;
>>> @@ -538,9 +544,7 @@ static int __init of_platform_default_populate_init(void)
>>>           }
>>>
>>>           /* Populate everything else. */
>>> -       fw_devlink_pause();
>>>           of_platform_default_populate(NULL, NULL, NULL);
>>> -       fw_devlink_resume();
>>>
>>>           return 0;
>>>    }
>>> @@ -548,6 +552,7 @@ arch_initcall_sync(of_platform_default_populate_init);
>>>
>>>    static int __init of_platform_sync_state_init(void)
>>>    {
>>> +       fw_devlink_resume();
>>
>> ^ it seems has to be done earlier, like
>> +static int __init of_platform_fw_devlink_resume(void)
>> +{
>> +       fw_devlink_resume();
>> +       return 0;
>> +}
>> +device_initcall_sync(of_platform_fw_devlink_resume);
> 
> This will mean no device will probe until device_initcall_sync().
> Unfortunately, I don't think we can make such a sweeping assumption.

Could you answer below questions, pls?
>>> By the way, is there option to disable this feature at all?
>>> Is there Kconfig option?

-- 
Best regards,
grygorii

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Rob Herring]

On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan <saravanak@google.com> wrote:
>
> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> adding all top level devices") optimized the fwnode parsing when all top
> level devices are added, it missed out optimizing this for platform
> where the top level devices are added through the init_machine() path.
>
> This commit does the optimization for all paths by simply moving the
> fw_devlink_pause/resume() inside of_platform_default_populate().
>
> Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> Signed-off-by: Saravana Kannan <saravanak@google.com>
> ---
>  drivers/of/platform.c | 19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 071f04da32c8..79972e49b539 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
>                                  const struct of_dev_auxdata *lookup,
>                                  struct device *parent)
>  {
> -       return of_platform_populate(root, of_default_bus_match_table, lookup,
> -                                   parent);
> +       int ret;
> +
> +       /*
> +        * fw_devlink_pause/resume() are only safe to be called around top
> +        * level device addition due to locking constraints.
> +        */
> +       if (!root)
> +               fw_devlink_pause();
> +
> +       ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> +                                  parent);

of_platform_default_populate() vs. of_platform_populate() is just a
different match table. I don't think the behavior should otherwise be
different.

There's also of_platform_probe() which has slightly different matching
behavior. It should not behave differently either with respect to
devlinks.

Rob

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Saravana Kannan]

On Fri, Oct 2, 2020 at 7:08 AM Rob Herring <robh+dt@kernel.org> wrote:
>
> On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan <saravanak@google.com> wrote:
> >
> > When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> > adding all top level devices") optimized the fwnode parsing when all top
> > level devices are added, it missed out optimizing this for platform
> > where the top level devices are added through the init_machine() path.
> >
> > This commit does the optimization for all paths by simply moving the
> > fw_devlink_pause/resume() inside of_platform_default_populate().
> >
> > Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > ---
> >  drivers/of/platform.c | 19 +++++++++++++++----
> >  1 file changed, 15 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > index 071f04da32c8..79972e49b539 100644
> > --- a/drivers/of/platform.c
> > +++ b/drivers/of/platform.c
> > @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
> >                                  const struct of_dev_auxdata *lookup,
> >                                  struct device *parent)
> >  {
> > -       return of_platform_populate(root, of_default_bus_match_table, lookup,
> > -                                   parent);
> > +       int ret;
> > +
> > +       /*
> > +        * fw_devlink_pause/resume() are only safe to be called around top
> > +        * level device addition due to locking constraints.
> > +        */
> > +       if (!root)
> > +               fw_devlink_pause();
> > +
> > +       ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> > +                                  parent);
>
> of_platform_default_populate() vs. of_platform_populate() is just a
> different match table. I don't think the behavior should otherwise be
> different.
>
> There's also of_platform_probe() which has slightly different matching
> behavior. It should not behave differently either with respect to
> devlinks.

So I'm trying to do this only when the top level devices are added for
the first time. of_platform_default_populate() seems to be the most
common path. For other cases, I think we just need to call
fw_devlink_pause/resume() wherever the top level devices are added for
the first time. As I said in the other email, we can't add
fw_devlink_pause/resume() by default to of_platform_populate().

Do you have other ideas for achieving "call fw_devlink_pause/resume()
only when top level devices are added for the first time"?

-Saravana

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Laurent Pinchart]

Hi Saravana,

On Fri, Oct 02, 2020 at 10:51:51AM -0700, Saravana Kannan wrote:
> On Fri, Oct 2, 2020 at 7:08 AM Rob Herring <robh+dt@kernel.org> wrote:
> > On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan <saravanak@google.com> wrote:
> > >
> > > When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> > > adding all top level devices") optimized the fwnode parsing when all top
> > > level devices are added, it missed out optimizing this for platform
> > > where the top level devices are added through the init_machine() path.
> > >
> > > This commit does the optimization for all paths by simply moving the
> > > fw_devlink_pause/resume() inside of_platform_default_populate().
> > >
> > > Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > > ---
> > >  drivers/of/platform.c | 19 +++++++++++++++----
> > >  1 file changed, 15 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > > index 071f04da32c8..79972e49b539 100644
> > > --- a/drivers/of/platform.c
> > > +++ b/drivers/of/platform.c
> > > @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
> > >                                  const struct of_dev_auxdata *lookup,
> > >                                  struct device *parent)
> > >  {
> > > -       return of_platform_populate(root, of_default_bus_match_table, lookup,
> > > -                                   parent);
> > > +       int ret;
> > > +
> > > +       /*
> > > +        * fw_devlink_pause/resume() are only safe to be called around top
> > > +        * level device addition due to locking constraints.
> > > +        */
> > > +       if (!root)
> > > +               fw_devlink_pause();
> > > +
> > > +       ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> > > +                                  parent);
> >
> > of_platform_default_populate() vs. of_platform_populate() is just a
> > different match table. I don't think the behavior should otherwise be
> > different.
> >
> > There's also of_platform_probe() which has slightly different matching
> > behavior. It should not behave differently either with respect to
> > devlinks.
> 
> So I'm trying to do this only when the top level devices are added for
> the first time. of_platform_default_populate() seems to be the most
> common path. For other cases, I think we just need to call
> fw_devlink_pause/resume() wherever the top level devices are added for
> the first time. As I said in the other email, we can't add
> fw_devlink_pause/resume() by default to of_platform_populate().
> 
> Do you have other ideas for achieving "call fw_devlink_pause/resume()
> only when top level devices are added for the first time"?

I'm not an expert in this domain, but before investigating it, would you
be able to share a hack patch that implements this (in the most simple
way) to check if it actually fixes the delays I experience on my system
?

-- 
Regards,

Laurent Pinchart

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Saravana Kannan]

On Fri, Oct 2, 2020 at 10:55 AM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Saravana,
>
> On Fri, Oct 02, 2020 at 10:51:51AM -0700, Saravana Kannan wrote:
> > On Fri, Oct 2, 2020 at 7:08 AM Rob Herring <robh+dt@kernel.org> wrote:
> > > On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan <saravanak@google.com> wrote:
> > > >
> > > > When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> > > > adding all top level devices") optimized the fwnode parsing when all top
> > > > level devices are added, it missed out optimizing this for platform
> > > > where the top level devices are added through the init_machine() path.
> > > >
> > > > This commit does the optimization for all paths by simply moving the
> > > > fw_devlink_pause/resume() inside of_platform_default_populate().
> > > >
> > > > Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > > > ---
> > > >  drivers/of/platform.c | 19 +++++++++++++++----
> > > >  1 file changed, 15 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > > > index 071f04da32c8..79972e49b539 100644
> > > > --- a/drivers/of/platform.c
> > > > +++ b/drivers/of/platform.c
> > > > @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
> > > >                                  const struct of_dev_auxdata *lookup,
> > > >                                  struct device *parent)
> > > >  {
> > > > -       return of_platform_populate(root, of_default_bus_match_table, lookup,
> > > > -                                   parent);
> > > > +       int ret;
> > > > +
> > > > +       /*
> > > > +        * fw_devlink_pause/resume() are only safe to be called around top
> > > > +        * level device addition due to locking constraints.
> > > > +        */
> > > > +       if (!root)
> > > > +               fw_devlink_pause();
> > > > +
> > > > +       ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> > > > +                                  parent);
> > >
> > > of_platform_default_populate() vs. of_platform_populate() is just a
> > > different match table. I don't think the behavior should otherwise be
> > > different.
> > >
> > > There's also of_platform_probe() which has slightly different matching
> > > behavior. It should not behave differently either with respect to
> > > devlinks.
> >
> > So I'm trying to do this only when the top level devices are added for
> > the first time. of_platform_default_populate() seems to be the most
> > common path. For other cases, I think we just need to call
> > fw_devlink_pause/resume() wherever the top level devices are added for
> > the first time. As I said in the other email, we can't add
> > fw_devlink_pause/resume() by default to of_platform_populate().
> >
> > Do you have other ideas for achieving "call fw_devlink_pause/resume()
> > only when top level devices are added for the first time"?
>
> I'm not an expert in this domain, but before investigating it, would you
> be able to share a hack patch that implements this (in the most simple
> way) to check if it actually fixes the delays I experience on my system
> ?

So I take it the patch I sent out didn't work for you? Can you tell me
what machine/DT you are using?

-Saravana

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Laurent Pinchart]

Hi Saravana,

On Fri, Oct 02, 2020 at 10:58:55AM -0700, Saravana Kannan wrote:
> On Fri, Oct 2, 2020 at 10:55 AM Laurent Pinchart wrote:
> > On Fri, Oct 02, 2020 at 10:51:51AM -0700, Saravana Kannan wrote:
> > > On Fri, Oct 2, 2020 at 7:08 AM Rob Herring <robh+dt@kernel.org> wrote:
> > > > On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan <saravanak@google.com> wrote:
> > > > >
> > > > > When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> > > > > adding all top level devices") optimized the fwnode parsing when all top
> > > > > level devices are added, it missed out optimizing this for platform
> > > > > where the top level devices are added through the init_machine() path.
> > > > >
> > > > > This commit does the optimization for all paths by simply moving the
> > > > > fw_devlink_pause/resume() inside of_platform_default_populate().
> > > > >
> > > > > Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > > > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > > > > ---
> > > > >  drivers/of/platform.c | 19 +++++++++++++++----
> > > > >  1 file changed, 15 insertions(+), 4 deletions(-)
> > > > >
> > > > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > > > > index 071f04da32c8..79972e49b539 100644
> > > > > --- a/drivers/of/platform.c
> > > > > +++ b/drivers/of/platform.c
> > > > > @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
> > > > >                                  const struct of_dev_auxdata *lookup,
> > > > >                                  struct device *parent)
> > > > >  {
> > > > > -       return of_platform_populate(root, of_default_bus_match_table, lookup,
> > > > > -                                   parent);
> > > > > +       int ret;
> > > > > +
> > > > > +       /*
> > > > > +        * fw_devlink_pause/resume() are only safe to be called around top
> > > > > +        * level device addition due to locking constraints.
> > > > > +        */
> > > > > +       if (!root)
> > > > > +               fw_devlink_pause();
> > > > > +
> > > > > +       ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> > > > > +                                  parent);
> > > >
> > > > of_platform_default_populate() vs. of_platform_populate() is just a
> > > > different match table. I don't think the behavior should otherwise be
> > > > different.
> > > >
> > > > There's also of_platform_probe() which has slightly different matching
> > > > behavior. It should not behave differently either with respect to
> > > > devlinks.
> > >
> > > So I'm trying to do this only when the top level devices are added for
> > > the first time. of_platform_default_populate() seems to be the most
> > > common path. For other cases, I think we just need to call
> > > fw_devlink_pause/resume() wherever the top level devices are added for
> > > the first time. As I said in the other email, we can't add
> > > fw_devlink_pause/resume() by default to of_platform_populate().
> > >
> > > Do you have other ideas for achieving "call fw_devlink_pause/resume()
> > > only when top level devices are added for the first time"?
> >
> > I'm not an expert in this domain, but before investigating it, would you
> > be able to share a hack patch that implements this (in the most simple
> > way) to check if it actually fixes the delays I experience on my system
> > ?
> 
> So I take it the patch I sent out didn't work for you? Can you tell me
> what machine/DT you are using?

I've replied to the patch:

Based on v5.9-rc5, before the patch:

[    0.652887] cpuidle: using governor menu
[   12.349476] No ATAGs?

After the patch:

[    0.650460] cpuidle: using governor menu
[   12.262101] No ATAGs?

I'm using an AM57xx EVM, whose DT is not upstream, but it's essentially
a am57xx-beagle-x15-revb1.dts (it includes that DTS) with a few
additional nodes for GPIO keys, LCD panel, backlight and touchscreen.

-- 
Regards,

Laurent Pinchart

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Grygorii Strashko]

hi Saravana,

On 02/10/2020 21:27, Laurent Pinchart wrote:
> Hi Saravana,
> 
> On Fri, Oct 02, 2020 at 10:58:55AM -0700, Saravana Kannan wrote:
>> On Fri, Oct 2, 2020 at 10:55 AM Laurent Pinchart wrote:
>>> On Fri, Oct 02, 2020 at 10:51:51AM -0700, Saravana Kannan wrote:
>>>> On Fri, Oct 2, 2020 at 7:08 AM Rob Herring <robh+dt@kernel.org> wrote:
>>>>> On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan <saravanak@google.com> wrote:
>>>>>>
>>>>>> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
>>>>>> adding all top level devices") optimized the fwnode parsing when all top
>>>>>> level devices are added, it missed out optimizing this for platform
>>>>>> where the top level devices are added through the init_machine() path.
>>>>>>
>>>>>> This commit does the optimization for all paths by simply moving the
>>>>>> fw_devlink_pause/resume() inside of_platform_default_populate().
>>>>>>
>>>>>> Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
>>>>>> Signed-off-by: Saravana Kannan <saravanak@google.com>
>>>>>> ---
>>>>>>   drivers/of/platform.c | 19 +++++++++++++++----
>>>>>>   1 file changed, 15 insertions(+), 4 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
>>>>>> index 071f04da32c8..79972e49b539 100644
>>>>>> --- a/drivers/of/platform.c
>>>>>> +++ b/drivers/of/platform.c
>>>>>> @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
>>>>>>                                   const struct of_dev_auxdata *lookup,
>>>>>>                                   struct device *parent)
>>>>>>   {
>>>>>> -       return of_platform_populate(root, of_default_bus_match_table, lookup,
>>>>>> -                                   parent);
>>>>>> +       int ret;
>>>>>> +
>>>>>> +       /*
>>>>>> +        * fw_devlink_pause/resume() are only safe to be called around top
>>>>>> +        * level device addition due to locking constraints.
>>>>>> +        */
>>>>>> +       if (!root)
>>>>>> +               fw_devlink_pause();
>>>>>> +
>>>>>> +       ret = of_platform_populate(root, of_default_bus_match_table, lookup,
>>>>>> +                                  parent);
>>>>>
>>>>> of_platform_default_populate() vs. of_platform_populate() is just a
>>>>> different match table. I don't think the behavior should otherwise be
>>>>> different.
>>>>>
>>>>> There's also of_platform_probe() which has slightly different matching
>>>>> behavior. It should not behave differently either with respect to
>>>>> devlinks.
>>>>
>>>> So I'm trying to do this only when the top level devices are added for
>>>> the first time. of_platform_default_populate() seems to be the most
>>>> common path. For other cases, I think we just need to call
>>>> fw_devlink_pause/resume() wherever the top level devices are added for
>>>> the first time. As I said in the other email, we can't add
>>>> fw_devlink_pause/resume() by default to of_platform_populate().
>>>>
>>>> Do you have other ideas for achieving "call fw_devlink_pause/resume()
>>>> only when top level devices are added for the first time"?
>>>
>>> I'm not an expert in this domain, but before investigating it, would you
>>> be able to share a hack patch that implements this (in the most simple
>>> way) to check if it actually fixes the delays I experience on my system
>>> ?
>>
>> So I take it the patch I sent out didn't work for you? Can you tell me
>> what machine/DT you are using?
> 
> I've replied to the patch:
> 
> Based on v5.9-rc5, before the patch:
> 
> [    0.652887] cpuidle: using governor menu
> [   12.349476] No ATAGs?
> 
> After the patch:
> 
> [    0.650460] cpuidle: using governor menu
> [   12.262101] No ATAGs?
> 
> I'm using an AM57xx EVM, whose DT is not upstream, but it's essentially
> a am57xx-beagle-x15-revb1.dts (it includes that DTS) with a few
> additional nodes for GPIO keys, LCD panel, backlight and touchscreen.
> 

hope you are receiving my mails as I've provided you with all required information already [1]

with below diff:
[    4.177231] Freeing unused kernel memory: 1024K
[    4.181892] Run /sbin/init as init process

The best time with [2] is
[    3.100483] Run /sbin/init as init process

Still 1 sec lose.

Pls understand an issue - requirements here are like 500ms boot with can, Ethernet, camera and display on ;(

[1] https://lore.kernel.org/patchwork/patch/1316134/#1511276
[2] https://lore.kernel.org/patchwork/patch/1316134/#1511435

diff --git a/arch/arm/mach-omap2/pdata-quirks.c b/arch/arm/mach-omap2/pdata-quirks.c
index 2a4fe3e68b82..ac1ab8928190 100644
--- a/arch/arm/mach-omap2/pdata-quirks.c
+++ b/arch/arm/mach-omap2/pdata-quirks.c
@@ -591,7 +591,9 @@ void __init pdata_quirks_init(const struct of_device_id *omap_dt_match_table)
         if (of_machine_is_compatible("ti,omap3"))
                 omap3_mcbsp_init();
         pdata_quirks_check(auxdata_quirks);
+       fw_devlink_pause();
         of_platform_populate(NULL, omap_dt_match_table,
                              omap_auxdata_lookup, NULL);
+       fw_devlink_resume();
         pdata_quirks_check(pdata_quirks);
  }


-- 
Best regards,
grygorii

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Saravana Kannan]

On Fri, Oct 2, 2020 at 11:35 AM 'Grygorii Strashko' via kernel-team
<kernel-team@android.com> wrote:
>
> hi Saravana,
>
> On 02/10/2020 21:27, Laurent Pinchart wrote:
> > Hi Saravana,
> >
> > On Fri, Oct 02, 2020 at 10:58:55AM -0700, Saravana Kannan wrote:
> >> On Fri, Oct 2, 2020 at 10:55 AM Laurent Pinchart wrote:
> >>> On Fri, Oct 02, 2020 at 10:51:51AM -0700, Saravana Kannan wrote:
> >>>> On Fri, Oct 2, 2020 at 7:08 AM Rob Herring <robh+dt@kernel.org> wrote:
> >>>>> On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan <saravanak@google.com> wrote:
> >>>>>>
> >>>>>> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> >>>>>> adding all top level devices") optimized the fwnode parsing when all top
> >>>>>> level devices are added, it missed out optimizing this for platform
> >>>>>> where the top level devices are added through the init_machine() path.
> >>>>>>
> >>>>>> This commit does the optimization for all paths by simply moving the
> >>>>>> fw_devlink_pause/resume() inside of_platform_default_populate().
> >>>>>>
> >>>>>> Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> >>>>>> Signed-off-by: Saravana Kannan <saravanak@google.com>
> >>>>>> ---
> >>>>>>   drivers/of/platform.c | 19 +++++++++++++++----
> >>>>>>   1 file changed, 15 insertions(+), 4 deletions(-)
> >>>>>>
> >>>>>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> >>>>>> index 071f04da32c8..79972e49b539 100644
> >>>>>> --- a/drivers/of/platform.c
> >>>>>> +++ b/drivers/of/platform.c
> >>>>>> @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
> >>>>>>                                   const struct of_dev_auxdata *lookup,
> >>>>>>                                   struct device *parent)
> >>>>>>   {
> >>>>>> -       return of_platform_populate(root, of_default_bus_match_table, lookup,
> >>>>>> -                                   parent);
> >>>>>> +       int ret;
> >>>>>> +
> >>>>>> +       /*
> >>>>>> +        * fw_devlink_pause/resume() are only safe to be called around top
> >>>>>> +        * level device addition due to locking constraints.
> >>>>>> +        */
> >>>>>> +       if (!root)
> >>>>>> +               fw_devlink_pause();
> >>>>>> +
> >>>>>> +       ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> >>>>>> +                                  parent);
> >>>>>
> >>>>> of_platform_default_populate() vs. of_platform_populate() is just a
> >>>>> different match table. I don't think the behavior should otherwise be
> >>>>> different.
> >>>>>
> >>>>> There's also of_platform_probe() which has slightly different matching
> >>>>> behavior. It should not behave differently either with respect to
> >>>>> devlinks.
> >>>>
> >>>> So I'm trying to do this only when the top level devices are added for
> >>>> the first time. of_platform_default_populate() seems to be the most
> >>>> common path. For other cases, I think we just need to call
> >>>> fw_devlink_pause/resume() wherever the top level devices are added for
> >>>> the first time. As I said in the other email, we can't add
> >>>> fw_devlink_pause/resume() by default to of_platform_populate().
> >>>>
> >>>> Do you have other ideas for achieving "call fw_devlink_pause/resume()
> >>>> only when top level devices are added for the first time"?
> >>>
> >>> I'm not an expert in this domain, but before investigating it, would you
> >>> be able to share a hack patch that implements this (in the most simple
> >>> way) to check if it actually fixes the delays I experience on my system
> >>> ?
> >>
> >> So I take it the patch I sent out didn't work for you? Can you tell me
> >> what machine/DT you are using?
> >
> > I've replied to the patch:
> >
> > Based on v5.9-rc5, before the patch:
> >
> > [    0.652887] cpuidle: using governor menu
> > [   12.349476] No ATAGs?
> >
> > After the patch:
> >
> > [    0.650460] cpuidle: using governor menu
> > [   12.262101] No ATAGs?
> >
> > I'm using an AM57xx EVM, whose DT is not upstream, but it's essentially
> > a am57xx-beagle-x15-revb1.dts (it includes that DTS) with a few
> > additional nodes for GPIO keys, LCD panel, backlight and touchscreen.
> >
>
> hope you are receiving my mails as I've provided you with all required information already [1]

Laurent/Grygorii,

Looks like I'm definitely missing emails. Sorry about the confusion.

I have some other urgent things on my plate right now. Is it okay if I
get to this in a day or two? In the end, we'll find a solution that
addresses most/all of the delay.

Thanks,
Saravana

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Laurent Pinchart]

Hi Saravana,

On Fri, Oct 02, 2020 at 12:56:30PM -0700, Saravana Kannan wrote:
> On Fri, Oct 2, 2020 at 11:35 AM 'Grygorii Strashko' via kernel-team wrote:
> > On 02/10/2020 21:27, Laurent Pinchart wrote:
> > > On Fri, Oct 02, 2020 at 10:58:55AM -0700, Saravana Kannan wrote:
> > >> On Fri, Oct 2, 2020 at 10:55 AM Laurent Pinchart wrote:
> > >>> On Fri, Oct 02, 2020 at 10:51:51AM -0700, Saravana Kannan wrote:
> > >>>> On Fri, Oct 2, 2020 at 7:08 AM Rob Herring <robh+dt@kernel.org> wrote:
> > >>>>> On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan <saravanak@google.com> wrote:
> > >>>>>>
> > >>>>>> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> > >>>>>> adding all top level devices") optimized the fwnode parsing when all top
> > >>>>>> level devices are added, it missed out optimizing this for platform
> > >>>>>> where the top level devices are added through the init_machine() path.
> > >>>>>>
> > >>>>>> This commit does the optimization for all paths by simply moving the
> > >>>>>> fw_devlink_pause/resume() inside of_platform_default_populate().
> > >>>>>>
> > >>>>>> Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > >>>>>> Signed-off-by: Saravana Kannan <saravanak@google.com>
> > >>>>>> ---
> > >>>>>>   drivers/of/platform.c | 19 +++++++++++++++----
> > >>>>>>   1 file changed, 15 insertions(+), 4 deletions(-)
> > >>>>>>
> > >>>>>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > >>>>>> index 071f04da32c8..79972e49b539 100644
> > >>>>>> --- a/drivers/of/platform.c
> > >>>>>> +++ b/drivers/of/platform.c
> > >>>>>> @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
> > >>>>>>                                   const struct of_dev_auxdata *lookup,
> > >>>>>>                                   struct device *parent)
> > >>>>>>   {
> > >>>>>> -       return of_platform_populate(root, of_default_bus_match_table, lookup,
> > >>>>>> -                                   parent);
> > >>>>>> +       int ret;
> > >>>>>> +
> > >>>>>> +       /*
> > >>>>>> +        * fw_devlink_pause/resume() are only safe to be called around top
> > >>>>>> +        * level device addition due to locking constraints.
> > >>>>>> +        */
> > >>>>>> +       if (!root)
> > >>>>>> +               fw_devlink_pause();
> > >>>>>> +
> > >>>>>> +       ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> > >>>>>> +                                  parent);
> > >>>>>
> > >>>>> of_platform_default_populate() vs. of_platform_populate() is just a
> > >>>>> different match table. I don't think the behavior should otherwise be
> > >>>>> different.
> > >>>>>
> > >>>>> There's also of_platform_probe() which has slightly different matching
> > >>>>> behavior. It should not behave differently either with respect to
> > >>>>> devlinks.
> > >>>>
> > >>>> So I'm trying to do this only when the top level devices are added for
> > >>>> the first time. of_platform_default_populate() seems to be the most
> > >>>> common path. For other cases, I think we just need to call
> > >>>> fw_devlink_pause/resume() wherever the top level devices are added for
> > >>>> the first time. As I said in the other email, we can't add
> > >>>> fw_devlink_pause/resume() by default to of_platform_populate().
> > >>>>
> > >>>> Do you have other ideas for achieving "call fw_devlink_pause/resume()
> > >>>> only when top level devices are added for the first time"?
> > >>>
> > >>> I'm not an expert in this domain, but before investigating it, would you
> > >>> be able to share a hack patch that implements this (in the most simple
> > >>> way) to check if it actually fixes the delays I experience on my system
> > >>> ?
> > >>
> > >> So I take it the patch I sent out didn't work for you? Can you tell me
> > >> what machine/DT you are using?
> > >
> > > I've replied to the patch:
> > >
> > > Based on v5.9-rc5, before the patch:
> > >
> > > [    0.652887] cpuidle: using governor menu
> > > [   12.349476] No ATAGs?
> > >
> > > After the patch:
> > >
> > > [    0.650460] cpuidle: using governor menu
> > > [   12.262101] No ATAGs?
> > >
> > > I'm using an AM57xx EVM, whose DT is not upstream, but it's essentially
> > > a am57xx-beagle-x15-revb1.dts (it includes that DTS) with a few
> > > additional nodes for GPIO keys, LCD panel, backlight and touchscreen.
> > >
> >
> > hope you are receiving my mails as I've provided you with all required information already [1]
> 
> Laurent/Grygorii,
> 
> Looks like I'm definitely missing emails. Sorry about the confusion.
> 
> I have some other urgent things on my plate right now. Is it okay if I
> get to this in a day or two? In the end, we'll find a solution that
> addresses most/all of the delay.

No issue on my side.

By the way, during initial investigations, I've traced code paths to
figure out if there was a particular step that would consume a large
amount of time, and found out that of_platform_populate() ends up
executing devlink-related code that seems to have an O(n^3) complexity
on the number of devices, with a few dozens of milliseconds for each
iteration. That's a very bad complexity.

-- 
Regards,

Laurent Pinchart

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Saravana Kannan]

On Fri, Oct 2, 2020 at 5:14 PM Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Saravana,
>
> On Fri, Oct 02, 2020 at 12:56:30PM -0700, Saravana Kannan wrote:
> > On Fri, Oct 2, 2020 at 11:35 AM 'Grygorii Strashko' via kernel-team wrote:
> > > On 02/10/2020 21:27, Laurent Pinchart wrote:
> > > > On Fri, Oct 02, 2020 at 10:58:55AM -0700, Saravana Kannan wrote:
> > > >> On Fri, Oct 2, 2020 at 10:55 AM Laurent Pinchart wrote:
> > > >>> On Fri, Oct 02, 2020 at 10:51:51AM -0700, Saravana Kannan wrote:
> > > >>>> On Fri, Oct 2, 2020 at 7:08 AM Rob Herring <robh+dt@kernel.org> wrote:
> > > >>>>> On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan <saravanak@google.com> wrote:
> > > >>>>>>
> > > >>>>>> When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> > > >>>>>> adding all top level devices") optimized the fwnode parsing when all top
> > > >>>>>> level devices are added, it missed out optimizing this for platform
> > > >>>>>> where the top level devices are added through the init_machine() path.
> > > >>>>>>
> > > >>>>>> This commit does the optimization for all paths by simply moving the
> > > >>>>>> fw_devlink_pause/resume() inside of_platform_default_populate().
> > > >>>>>>
> > > >>>>>> Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > > >>>>>> Signed-off-by: Saravana Kannan <saravanak@google.com>
> > > >>>>>> ---
> > > >>>>>>   drivers/of/platform.c | 19 +++++++++++++++----
> > > >>>>>>   1 file changed, 15 insertions(+), 4 deletions(-)
> > > >>>>>>
> > > >>>>>> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > > >>>>>> index 071f04da32c8..79972e49b539 100644
> > > >>>>>> --- a/drivers/of/platform.c
> > > >>>>>> +++ b/drivers/of/platform.c
> > > >>>>>> @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
> > > >>>>>>                                   const struct of_dev_auxdata *lookup,
> > > >>>>>>                                   struct device *parent)
> > > >>>>>>   {
> > > >>>>>> -       return of_platform_populate(root, of_default_bus_match_table, lookup,
> > > >>>>>> -                                   parent);
> > > >>>>>> +       int ret;
> > > >>>>>> +
> > > >>>>>> +       /*
> > > >>>>>> +        * fw_devlink_pause/resume() are only safe to be called around top
> > > >>>>>> +        * level device addition due to locking constraints.
> > > >>>>>> +        */
> > > >>>>>> +       if (!root)
> > > >>>>>> +               fw_devlink_pause();
> > > >>>>>> +
> > > >>>>>> +       ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> > > >>>>>> +                                  parent);
> > > >>>>>
> > > >>>>> of_platform_default_populate() vs. of_platform_populate() is just a
> > > >>>>> different match table. I don't think the behavior should otherwise be
> > > >>>>> different.
> > > >>>>>
> > > >>>>> There's also of_platform_probe() which has slightly different matching
> > > >>>>> behavior. It should not behave differently either with respect to
> > > >>>>> devlinks.
> > > >>>>
> > > >>>> So I'm trying to do this only when the top level devices are added for
> > > >>>> the first time. of_platform_default_populate() seems to be the most
> > > >>>> common path. For other cases, I think we just need to call
> > > >>>> fw_devlink_pause/resume() wherever the top level devices are added for
> > > >>>> the first time. As I said in the other email, we can't add
> > > >>>> fw_devlink_pause/resume() by default to of_platform_populate().
> > > >>>>
> > > >>>> Do you have other ideas for achieving "call fw_devlink_pause/resume()
> > > >>>> only when top level devices are added for the first time"?
> > > >>>
> > > >>> I'm not an expert in this domain, but before investigating it, would you
> > > >>> be able to share a hack patch that implements this (in the most simple
> > > >>> way) to check if it actually fixes the delays I experience on my system
> > > >>> ?
> > > >>
> > > >> So I take it the patch I sent out didn't work for you? Can you tell me
> > > >> what machine/DT you are using?
> > > >
> > > > I've replied to the patch:
> > > >
> > > > Based on v5.9-rc5, before the patch:
> > > >
> > > > [    0.652887] cpuidle: using governor menu
> > > > [   12.349476] No ATAGs?
> > > >
> > > > After the patch:
> > > >
> > > > [    0.650460] cpuidle: using governor menu
> > > > [   12.262101] No ATAGs?
> > > >
> > > > I'm using an AM57xx EVM, whose DT is not upstream, but it's essentially
> > > > a am57xx-beagle-x15-revb1.dts (it includes that DTS) with a few
> > > > additional nodes for GPIO keys, LCD panel, backlight and touchscreen.
> > > >
> > >
> > > hope you are receiving my mails as I've provided you with all required information already [1]
> >
> > Laurent/Grygorii,
> >
> > Looks like I'm definitely missing emails. Sorry about the confusion.
> >
> > I have some other urgent things on my plate right now. Is it okay if I
> > get to this in a day or two? In the end, we'll find a solution that
> > addresses most/all of the delay.
>
> No issue on my side.

Hi Laurent,

Sorry it took awhile for me to get back to this.

Can you try throwing around fw_devlink_pause/resume() around the
of_platform_populate() call in arch/arm/mach-omap2/pdata-quirks.c?
Just trying to verify the cause/fix.

If it fixes the issue, then considering Rob's comments [1], a good
short term solution might be to have the suggestion above and some way
to do pause/resume only when the top level devices are added.

> By the way, during initial investigations, I've traced code paths to
> figure out if there was a particular step that would consume a large
> amount of time, and found out that of_platform_populate() ends up
> executing devlink-related code that seems to have an O(n^3) complexity
> on the number of devices, with a few dozens of milliseconds for each
> iteration. That's a very bad complexity.

As you said, the complexity of fw_devlink parsing can be O(N^2). There
are other ways to improve it to make it O(N) but it has a bunch of
additional complexity and memory increase. When I tried to do it that
way the first time, I was question whether O(N^2) actually translated
to measurable difference. Looks like we do now :) I have something in
mind for how to do it with O(N) complexity, but I expect it to take a
while to get in. So in the meantime, I'm thinking of using
fw_devlink_pause/resume() as a short term optimization.

-Saravana

[1] - https://lore.kernel.org/linux-omap/CAL_Jsq+6mxtFei3+1ic4c5XCftJ8nZK6_S5_d15yEXQ02BTNKw@mail.gmail.com/

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Tomi Valkeinen]

On 27/10/2020 05:29, Saravana Kannan wrote:

> Can you try throwing around fw_devlink_pause/resume() around the
> of_platform_populate() call in arch/arm/mach-omap2/pdata-quirks.c?
> Just trying to verify the cause/fix.

AM5 EVM on v5.10-rc1:

[    1.139945] cpuidle: using governor menu
[   13.126461] No ATAGs?

After adding fw_devlink_pause/resume around of_platform_populate:

[    1.139587] cpuidle: using governor menu
[    1.899913] No ATAGs?

 Tomi

-- 
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki

Re: [PATCH v1] of: platform: Batch fwnode parsing in the init_machine() path

[Rob Herring]

On Fri, Oct 2, 2020 at 12:52 PM Saravana Kannan <saravanak@google.com> wrote:
>
> On Fri, Oct 2, 2020 at 7:08 AM Rob Herring <robh+dt@kernel.org> wrote:
> >
> > On Thu, Oct 1, 2020 at 5:59 PM Saravana Kannan <saravanak@google.com> wrote:
> > >
> > > When commit 93d2e4322aa7 ("of: platform: Batch fwnode parsing when
> > > adding all top level devices") optimized the fwnode parsing when all top
> > > level devices are added, it missed out optimizing this for platform
> > > where the top level devices are added through the init_machine() path.
> > >
> > > This commit does the optimization for all paths by simply moving the
> > > fw_devlink_pause/resume() inside of_platform_default_populate().
> > >
> > > Reported-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> > > Signed-off-by: Saravana Kannan <saravanak@google.com>
> > > ---
> > >  drivers/of/platform.c | 19 +++++++++++++++----
> > >  1 file changed, 15 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> > > index 071f04da32c8..79972e49b539 100644
> > > --- a/drivers/of/platform.c
> > > +++ b/drivers/of/platform.c
> > > @@ -501,8 +501,21 @@ int of_platform_default_populate(struct device_node *root,
> > >                                  const struct of_dev_auxdata *lookup,
> > >                                  struct device *parent)
> > >  {
> > > -       return of_platform_populate(root, of_default_bus_match_table, lookup,
> > > -                                   parent);
> > > +       int ret;
> > > +
> > > +       /*
> > > +        * fw_devlink_pause/resume() are only safe to be called around top
> > > +        * level device addition due to locking constraints.
> > > +        */
> > > +       if (!root)
> > > +               fw_devlink_pause();
> > > +
> > > +       ret = of_platform_populate(root, of_default_bus_match_table, lookup,
> > > +                                  parent);
> >
> > of_platform_default_populate() vs. of_platform_populate() is just a
> > different match table. I don't think the behavior should otherwise be
> > different.
> >
> > There's also of_platform_probe() which has slightly different matching
> > behavior. It should not behave differently either with respect to
> > devlinks.
>
> So I'm trying to do this only when the top level devices are added for
> the first time. of_platform_default_populate() seems to be the most
> common path. For other cases, I think we just need to call
> fw_devlink_pause/resume() wherever the top level devices are added for
> the first time.

> As I said in the other email, we can't add
> fw_devlink_pause/resume() by default to of_platform_populate().

If you detect it's the first time, you could?

>
> Do you have other ideas for achieving "call fw_devlink_pause/resume()
> only when top level devices are added for the first time"?

Eliminate the cases not using of_platform_default_populate().

There's 2 main reasons for the non default cases. The first is
auxdata. Really, for any modern platform that people care about (and
care about the boot time), they should not be using auxdata. That's
just for the DT transition. You know, a temporary thing from 9 years
ago.

The 2nd is having some parent device. This is typically an soc_device.
I really think this is kind of dumb. We should either have the parent
device always or never. After all, everything's an SoC right? Of
course changing that will break some Android systems since they like
to use non-ABI sysfs device paths.

There could also be some initcall ordering issues. IIRC, in the last
round of cleanups in this area, at91 gpio/pinctrl had an issue with
that. I think I have a half done fix for that I started.

Rob