* [RFD] Add debugfs for cpuidle ?
@ 2018-05-24 8:14 Daniel Lezcano
2018-05-24 8:28 ` Rafael J. Wysocki
0 siblings, 1 reply; 6+ messages in thread
From: Daniel Lezcano @ 2018-05-24 8:14 UTC (permalink / raw)
To: Rafael J. Wysocki; +Cc: Linux Kernel Mailing List, Linux PM mailing list
Hi all,
would it be interesting to add debugfs metrics for cpuidle in order to
read some statistics from there and investigate the behavior ?
--
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFD] Add debugfs for cpuidle ?
2018-05-24 8:14 [RFD] Add debugfs for cpuidle ? Daniel Lezcano
@ 2018-05-24 8:28 ` Rafael J. Wysocki
2018-05-24 8:47 ` Daniel Lezcano
0 siblings, 1 reply; 6+ messages in thread
From: Rafael J. Wysocki @ 2018-05-24 8:28 UTC (permalink / raw)
To: Daniel Lezcano; +Cc: Linux Kernel Mailing List, Linux PM mailing list
On Thursday, May 24, 2018 10:14:31 AM CEST Daniel Lezcano wrote:
>
> Hi all,
Hi,
> would it be interesting to add debugfs metrics for cpuidle in order to
> read some statistics from there and investigate the behavior ?
What exactly would you like to see in there?
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFD] Add debugfs for cpuidle ?
2018-05-24 8:28 ` Rafael J. Wysocki
@ 2018-05-24 8:47 ` Daniel Lezcano
2018-05-24 9:39 ` Rafael J. Wysocki
2018-08-30 8:22 ` Ulf Hansson
0 siblings, 2 replies; 6+ messages in thread
From: Daniel Lezcano @ 2018-05-24 8:47 UTC (permalink / raw)
To: Rafael J. Wysocki; +Cc: Linux Kernel Mailing List, Linux PM mailing list
On 24/05/2018 10:28, Rafael J. Wysocki wrote:
> On Thursday, May 24, 2018 10:14:31 AM CEST Daniel Lezcano wrote:
>>
>> Hi all,
>
> Hi,
>
>> would it be interesting to add debugfs metrics for cpuidle in order
>> to read some statistics from there and investigate the behavior ?
>
> What exactly would you like to see in there?
It could be interesting to have statistics on a per cpu and global basis
for:
- prediction accuracy:
/sys/kernel/debug/cpuidle/prediction/[good|over|under]
/sys/kernel/debug/cpuidle/cpu*/state*/prediction/[good|over|under]
- exit latency
In addition, it is often the case the idle states values are dropped
randomly, it is interesting to see the average exit latency for the
states. That could give also an indication the cluster idle state success.
/sys/kernel/debug/cpuidle/state*/latency/[min|max|avg|stddev]
/sys/kernel/debug/cpuidle/cpu*/state*/prediction/[min|max|avg|stddev]
And perhaps more information like the tick stopped stat ?
--
<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
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFD] Add debugfs for cpuidle ?
2018-05-24 8:47 ` Daniel Lezcano
@ 2018-05-24 9:39 ` Rafael J. Wysocki
2018-08-30 8:22 ` Ulf Hansson
1 sibling, 0 replies; 6+ messages in thread
From: Rafael J. Wysocki @ 2018-05-24 9:39 UTC (permalink / raw)
To: Daniel Lezcano; +Cc: Linux Kernel Mailing List, Linux PM mailing list
On Thursday, May 24, 2018 10:47:54 AM CEST Daniel Lezcano wrote:
> On 24/05/2018 10:28, Rafael J. Wysocki wrote:
> > On Thursday, May 24, 2018 10:14:31 AM CEST Daniel Lezcano wrote:
> >>
> >> Hi all,
> >
> > Hi,
> >
> >> would it be interesting to add debugfs metrics for cpuidle in order
> >> to read some statistics from there and investigate the behavior ?
> >
> > What exactly would you like to see in there?
>
> It could be interesting to have statistics on a per cpu and global basis
> for:
>
> - prediction accuracy:
>
> /sys/kernel/debug/cpuidle/prediction/[good|over|under]
> /sys/kernel/debug/cpuidle/cpu*/state*/prediction/[good|over|under]
>
> - exit latency
>
> In addition, it is often the case the idle states values are dropped
> randomly, it is interesting to see the average exit latency for the
> states. That could give also an indication the cluster idle state success.
>
> /sys/kernel/debug/cpuidle/state*/latency/[min|max|avg|stddev]
> /sys/kernel/debug/cpuidle/cpu*/state*/prediction/[min|max|avg|stddev]
>
> And perhaps more information like the tick stopped stat ?
Fair enough, but that must be minimum overhead.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFD] Add debugfs for cpuidle ?
2018-05-24 8:47 ` Daniel Lezcano
2018-05-24 9:39 ` Rafael J. Wysocki
@ 2018-08-30 8:22 ` Ulf Hansson
2018-08-30 8:24 ` Daniel Lezcano
1 sibling, 1 reply; 6+ messages in thread
From: Ulf Hansson @ 2018-08-30 8:22 UTC (permalink / raw)
To: Daniel Lezcano
Cc: Rafael J. Wysocki, Linux Kernel Mailing List, Linux PM mailing list
On 24 May 2018 at 10:47, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
> On 24/05/2018 10:28, Rafael J. Wysocki wrote:
>> On Thursday, May 24, 2018 10:14:31 AM CEST Daniel Lezcano wrote:
>>>
>>> Hi all,
>>
>> Hi,
>>
>>> would it be interesting to add debugfs metrics for cpuidle in order
>>> to read some statistics from there and investigate the behavior ?
>>
>> What exactly would you like to see in there?
>
> It could be interesting to have statistics on a per cpu and global basis
> for:
>
> - prediction accuracy:
>
> /sys/kernel/debug/cpuidle/prediction/[good|over|under]
> /sys/kernel/debug/cpuidle/cpu*/state*/prediction/[good|over|under]
>
> - exit latency
>
> In addition, it is often the case the idle states values are dropped
> randomly, it is interesting to see the average exit latency for the
> states. That could give also an indication the cluster idle state success.
>
> /sys/kernel/debug/cpuidle/state*/latency/[min|max|avg|stddev]
> /sys/kernel/debug/cpuidle/cpu*/state*/prediction/[min|max|avg|stddev]
>
> And perhaps more information like the tick stopped stat ?
>
Daniel,
Any chance that you have some draft version of actual code implementing this?
I would be very interested to try then - or help out to implement
this, in case you haven't started yet.
Kind regards
Uffe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFD] Add debugfs for cpuidle ?
2018-08-30 8:22 ` Ulf Hansson
@ 2018-08-30 8:24 ` Daniel Lezcano
0 siblings, 0 replies; 6+ messages in thread
From: Daniel Lezcano @ 2018-08-30 8:24 UTC (permalink / raw)
To: Ulf Hansson
Cc: Rafael J. Wysocki, Linux Kernel Mailing List, Linux PM mailing list
On 30/08/2018 10:22, Ulf Hansson wrote:
> On 24 May 2018 at 10:47, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
>> On 24/05/2018 10:28, Rafael J. Wysocki wrote:
>>> On Thursday, May 24, 2018 10:14:31 AM CEST Daniel Lezcano wrote:
>>>>
>>>> Hi all,
>>>
>>> Hi,
>>>
>>>> would it be interesting to add debugfs metrics for cpuidle in order
>>>> to read some statistics from there and investigate the behavior ?
>>>
>>> What exactly would you like to see in there?
>>
>> It could be interesting to have statistics on a per cpu and global basis
>> for:
>>
>> - prediction accuracy:
>>
>> /sys/kernel/debug/cpuidle/prediction/[good|over|under]
>> /sys/kernel/debug/cpuidle/cpu*/state*/prediction/[good|over|under]
>>
>> - exit latency
>>
>> In addition, it is often the case the idle states values are dropped
>> randomly, it is interesting to see the average exit latency for the
>> states. That could give also an indication the cluster idle state success.
>>
>> /sys/kernel/debug/cpuidle/state*/latency/[min|max|avg|stddev]
>> /sys/kernel/debug/cpuidle/cpu*/state*/prediction/[min|max|avg|stddev]
>>
>> And perhaps more information like the tick stopped stat ?
>>
>
> Daniel,
>
> Any chance that you have some draft version of actual code implementing this?
>
> I would be very interested to try then - or help out to implement
> this, in case you haven't started yet.
Yes, I have a draft version, a bit incomplete but easy to fill. I'm just
not fully convinced about the metrics we need yet.
--
<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
^ permalink raw reply [flat|nested] 6+ messages in thread
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2018-05-24 8:14 [RFD] Add debugfs for cpuidle ? Daniel Lezcano
2018-05-24 8:28 ` Rafael J. Wysocki
2018-05-24 8:47 ` Daniel Lezcano
2018-05-24 9:39 ` Rafael J. Wysocki
2018-08-30 8:22 ` Ulf Hansson
2018-08-30 8:24 ` Daniel Lezcano
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