Re: perf/x86/intel/uncore

[Song Liu <songliubraving@fb.com>]

> On Jan 25, 2019, at 1:35 PM, Liang, Kan <kan.liang@linux.intel.com> wrote:
> 
> 
> 
> On 1/25/2019 3:16 PM, Song Liu wrote:
>> Thanks Kan!
>>> On Jan 25, 2019, at 12:08 PM, Liang, Kan <kan.liang@linux.intel.com> wrote:
>>> 
>>> 
>>> 
>>> On 1/25/2019 1:54 PM, Song Liu wrote:
>>>> Hi,
>>>> We are debugging an issue that skx_pci_uncores cannot be registered on
>>>> 8-socket system with Xeon Platinum 8176 CPUs. After poking around for a
>>>> while, I found it is caused by snbep_pci2phy_map_init() couldn't find
>>>> a unbox_dev:
>>>>   ubox_dev = pci_get_device(PCI_VENDOR_ID_INTEL, devid, ubox_dev);
>>>>   unbox_dev == NULL
>>>>   ...
>>>> The same kernel (Linus' master) works fine on some single socket SKX
>>>> systems.
>>>> I am not sure what to check next. And I am not sure whether this is
>>>> specific to this system (HPE Superdome Flex).
>>> 
>>> Could you please share the offset 0xC0 and 0xD4 of the PCI configuration space for each device which PCI ID is 0x2014?
>>> 
>>> snbep_pci2phy_map_init() tries to build a mapping from BUS# to Socket ID.
>>> CPUNODEID (0xc0) discloses the Node ID of current BUS.
>>> GIDNIDMAP (0xd4) discloses the mapping between Socket ID and Node ID.
>>> 
>>> Here is an example from a 4 socket SKX.
>>> BUS    CPUNODEID(bit2:0)    GIDNIDMAP
>>> 0x0    0x0            0x688
>>> 0x40    0x1            0x688
>>> 0x80    0x2            0x688
>>> 0xC0    0x3            0x688
>>> 
>> Here is the data I get:
>> # lspci -xxx | grep "86 80 14 20" -A 15 -B 1 | grep -e "86 80 14 20" -e c0: -e d0: -e Intel
>> 0000:00:08.0 System peripheral: Intel Corporation Sky Lake-E Ubox Registers (rev 04)
>> 00: 86 80 14 20 00 00 10 00 04 00 80 08 00 00 80 00
>> c0: 00 a0 00 00 2f 00 00 80 01 00 02 00 2f 2f 2f 20
>> d0: 02 00 00 00 88 d6 b6 00 01 00 00 00 00 00 00 00
>> 0001:00:08.0 System peripheral: Intel Corporation Sky Lake-E Ubox Registers (rev 04)
>> 00: 86 80 14 20 00 00 10 00 04 00 80 08 00 00 80 00
>> c0: 01 80 00 00 1f 00 00 80 01 00 02 00 1f 1f 1f 10
>> d0: 02 00 00 00 88 46 92 00 01 00 00 00 00 00 00 00
>> 0002:00:08.0 System peripheral: Intel Corporation Sky Lake-E Ubox Registers (rev 04)
>> 00: 86 80 14 20 00 00 10 00 04 00 80 08 00 00 80 00
>> c0: 02 e0 00 00 8f 00 00 80 01 00 02 00 8f 8f 8f 80
>> d0: 02 00 00 00 88 f6 ff 00 01 00 00 00 00 00 00 00
>> 0003:00:08.0 System peripheral: Intel Corporation Sky Lake-E Ubox Registers (rev 04)
>> 00: 86 80 14 20 00 00 10 00 04 00 80 08 00 00 80 00
>> c0: 03 c0 00 00 4f 00 00 80 01 00 02 00 4f 4f 4f 40
>> d0: 02 00 00 00 88 66 db 00 01 00 00 00 00 00 00 00
>> 0004:00:08.0 System peripheral: Intel Corporation Sky Lake-E Ubox Registers (rev 04)
>> 00: 86 80 14 20 00 00 10 00 04 00 80 08 00 00 80 00
>> c0: a0 b4 00 00 2f 00 00 80 01 00 02 00 2f 2f 2f 20
> 
> The local node ID should be bit2:0. We didn't mask it in our codes.
> Does the patch as below work?
> 
> diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
> index c07bee3..15a8e3c 100644
> --- a/arch/x86/events/intel/uncore_snbep.c
> +++ b/arch/x86/events/intel/uncore_snbep.c
> @@ -1222,6 +1222,8 @@ static struct pci_driver snbep_uncore_pci_driver = {
> 	.id_table	= snbep_uncore_pci_ids,
> };
> 
> +#define NODE_ID_MASK	0x7
> +
> /*
>  * build pci bus to socket mapping
>  */
> @@ -1243,7 +1245,7 @@ static int snbep_pci2phy_map_init(int devid, int nodeid_loc, int idmap_loc, bool
> 		err = pci_read_config_dword(ubox_dev, nodeid_loc, &config);
> 		if (err)
> 			break;
> -		nodeid = config;
> +		nodeid = config & NODE_ID_MASK;
> 		/* get the Node ID mapping */
> 		err = pci_read_config_dword(ubox_dev, idmap_loc, &config);
> 		if (err)
> 
> 
> Thanks,
> Kan

Yes, this patch works! Now I can see uncore_imc_0 etc. Thanks Kan!

I also noticed that uncore_pci_probe() returns at 

        if (atomic_inc_return(&pmu->activeboxes) > 1)
                return 0;

for bus 1-7. So we only probed bus 0 (socket 0). Is this expected behavior?

Thanks again!
Song

>> d0: 02 00 00 00 6d 8b 68 00 01 00 00 00 00 00 00 00
>> 0005:00:08.0 System peripheral: Intel Corporation Sky Lake-E Ubox Registers (rev 04)
>> 00: 86 80 14 20 00 00 10 00 04 00 80 08 00 00 80 00
>> c0: 81 90 00 00 1f 00 00 80 01 00 02 00 1f 1f 1f 10
>> d0: 02 00 00 00 24 89 68 00 01 00 00 00 00 00 00 00
>> 0006:00:08.0 System peripheral: Intel Corporation Sky Lake-E Ubox Registers (rev 04)
>> 00: 86 80 14 20 00 00 10 00 04 00 80 08 00 00 80 00
>> c0: e2 fc 00 00 8f 00 00 80 01 00 02 00 8f 8f 8f 80
>> d0: 02 00 00 00 ff 8f 68 00 01 00 00 00 00 00 00 00
>> 0007:00:08.0 System peripheral: Intel Corporation Sky Lake-E Ubox Registers (rev 04)
>> 00: 86 80 14 20 00 00 10 00 04 00 80 08 00 00 80 00
>> c0: c3 d8 00 00 4f 00 00 80 01 00 02 00 4f 4f 4f 40
>> d0: 02 00 00 00 b6 8d 68 00 01 00 00 00 00 00 00 00
>> Song
>>> 
>>>> One thing I noticed is that the PCI configuration space shows
>>>> subsystem vendor ID of 0x1590 instead of 0x8086:
>>>> 0000:00:08.0 System peripheral: Intel Corporation Sky Lake-E Ubox Registers (rev 04)
>>>> 00: 86 80 14 20 00 00 10 00 04 00 80 08 00 00 80 00
>>>> 10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>>>> 20: 00 00 00 00 00 00 00 00 00 00 00 00 90 15 14 20   << subsystem vendor
>>>> 30: 00 00 00 00 40 00 00 00 00 00 00 00 00 00 00 00
>>>> But I don't think that is the problem as the code search with PCI_ANY_ID.
>>>> 
>>> 
>>> It looks for the device with PCI ID 0x2014.
>>> 
>>> 
>>> Thanks,
>>> Kan