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* Question regarding broadcast timer/cpuidle and /proc/interrupts
@ 2013-01-21 14:17 Daniel Lezcano
  2013-01-21 14:38 ` Santosh Shilimkar
  0 siblings, 1 reply; 3+ messages in thread
From: Daniel Lezcano @ 2013-01-21 14:17 UTC (permalink / raw)
  To: linux-omap, Lists Linaro-dev


Hi All,

I have a question regarding the behavior of cpuidle on pandaboard.

1. cpuidle is enabled

2. The deep idle states seem to be reach

for i in $(find /sys/devices/system/cpu -name "usage"); do echo "$i :
$(cat $i)"; done
/sys/devices/system/cpu/cpu0/cpuidle/state0/usage : 7049
/sys/devices/system/cpu/cpu0/cpuidle/state1/usage : 17
/sys/devices/system/cpu/cpu0/cpuidle/state2/usage : 1341
/sys/devices/system/cpu/cpu1/cpuidle/state0/usage : 6318
/sys/devices/system/cpu/cpu1/cpuidle/state1/usage : 17
/sys/devices/system/cpu/cpu1/cpuidle/state2/usage : 1341

3. Regarding the cpuidle driver code : the "state1" and "state2" are
coupled states where the broadcast timer is used instead of the local
timer. I assume this is because they go down when we reach these idle
states.

4. The content of /proc/interrupts shows no broadcast timer used at all.

...
IPI1:          0          0  Timer broadcast interrupts
...

Shouldn't be the broadcast timer used sometimes ? or did I miss something ?

Thanks.

  -- Daniel


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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Question regarding broadcast timer/cpuidle and /proc/interrupts
  2013-01-21 14:17 Question regarding broadcast timer/cpuidle and /proc/interrupts Daniel Lezcano
@ 2013-01-21 14:38 ` Santosh Shilimkar
  2013-01-21 14:39   ` Daniel Lezcano
  0 siblings, 1 reply; 3+ messages in thread
From: Santosh Shilimkar @ 2013-01-21 14:38 UTC (permalink / raw)
  To: Daniel Lezcano; +Cc: linux-omap, Lists Linaro-dev

On Monday 21 January 2013 07:47 PM, Daniel Lezcano wrote:
>
> Hi All,
>
> I have a question regarding the behavior of cpuidle on pandaboard.
>
> 1. cpuidle is enabled
>
> 2. The deep idle states seem to be reach
>
> for i in $(find /sys/devices/system/cpu -name "usage"); do echo "$i :
> $(cat $i)"; done
> /sys/devices/system/cpu/cpu0/cpuidle/state0/usage : 7049
> /sys/devices/system/cpu/cpu0/cpuidle/state1/usage : 17
> /sys/devices/system/cpu/cpu0/cpuidle/state2/usage : 1341
> /sys/devices/system/cpu/cpu1/cpuidle/state0/usage : 6318
> /sys/devices/system/cpu/cpu1/cpuidle/state1/usage : 17
> /sys/devices/system/cpu/cpu1/cpuidle/state2/usage : 1341
>
> 3. Regarding the cpuidle driver code : the "state1" and "state2" are
> coupled states where the broadcast timer is used instead of the local
> timer. I assume this is because they go down when we reach these idle
> states.
>
Thats correct. Local timer are not wakeup capable and hence we switch
to a wakeup capable broadcast timer.

> 4. The content of /proc/interrupts shows no broadcast timer used at all.
>
> ...
> IPI1:          0          0  Timer broadcast interrupts
> ...
>
> Shouldn't be the broadcast timer used sometimes ? or did I miss something ?
>
There might be an issue with status updating. Just look for gptimer1
interrupts. if they are incrementing then, broadcast is being used
but just the status update isn't happening some how.

regards
santosh


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Question regarding broadcast timer/cpuidle and /proc/interrupts
  2013-01-21 14:38 ` Santosh Shilimkar
@ 2013-01-21 14:39   ` Daniel Lezcano
  0 siblings, 0 replies; 3+ messages in thread
From: Daniel Lezcano @ 2013-01-21 14:39 UTC (permalink / raw)
  To: Santosh Shilimkar; +Cc: linux-omap, Lists Linaro-dev

On 01/21/2013 03:38 PM, Santosh Shilimkar wrote:
> On Monday 21 January 2013 07:47 PM, Daniel Lezcano wrote:
>>
>> Hi All,
>>
>> I have a question regarding the behavior of cpuidle on pandaboard.
>>
>> 1. cpuidle is enabled
>>
>> 2. The deep idle states seem to be reach
>>
>> for i in $(find /sys/devices/system/cpu -name "usage"); do echo "$i :
>> $(cat $i)"; done
>> /sys/devices/system/cpu/cpu0/cpuidle/state0/usage : 7049
>> /sys/devices/system/cpu/cpu0/cpuidle/state1/usage : 17
>> /sys/devices/system/cpu/cpu0/cpuidle/state2/usage : 1341
>> /sys/devices/system/cpu/cpu1/cpuidle/state0/usage : 6318
>> /sys/devices/system/cpu/cpu1/cpuidle/state1/usage : 17
>> /sys/devices/system/cpu/cpu1/cpuidle/state2/usage : 1341
>>
>> 3. Regarding the cpuidle driver code : the "state1" and "state2" are
>> coupled states where the broadcast timer is used instead of the local
>> timer. I assume this is because they go down when we reach these idle
>> states.
>>
> Thats correct. Local timer are not wakeup capable and hence we switch
> to a wakeup capable broadcast timer.
> 
>> 4. The content of /proc/interrupts shows no broadcast timer used at all.
>>
>> ...
>> IPI1:          0          0  Timer broadcast interrupts
>> ...
>>
>> Shouldn't be the broadcast timer used sometimes ? or did I miss
>> something ?
>>
> There might be an issue with status updating. Just look for gptimer1
> interrupts. if they are incrementing then, broadcast is being used
> but just the status update isn't happening some how.

Is it the interrupt 69 ?

 29:        293        395       GIC  twd
 41:          0          0       GIC  l3-dbg-irq
 42:          0          0       GIC  l3-app-irq
 44:          0          0       GIC  DMA
 69:         61          0       GIC  gp_timer
 88:          0          0       GIC  i2c.9
 89:          0          0       GIC  i2c.10
 93:          0          0       GIC  i2c.11
 94:          0          0       GIC  i2c.12
106:         93          0       GIC  OMAP UART2
169:          0          0      PRCM  hwmod_io
IPI0:         0          0  Timer broadcast interrupts
IPI1:      1424       1260  Rescheduling interrupts
IPI2:         0          0  Function call interrupts
IPI3:        81         90  Single function call interrupts
IPI4:         0          0  CPU stop interrupts
Err:          0

> 
> regards
> santosh
> 


-- 
 <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog

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^ permalink raw reply	[flat|nested] 3+ messages in thread

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2013-01-21 14:17 Question regarding broadcast timer/cpuidle and /proc/interrupts Daniel Lezcano
2013-01-21 14:38 ` Santosh Shilimkar
2013-01-21 14:39   ` Daniel Lezcano

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