cpuset configuration and measurements for power management

Vincent Guittot vincent.guittot at linaro.org
Tue Aug 30 09:21:30 UTC 2011


Hi Tony,

On 30 August 2011 10:51, Tony Mansson <tony.mansson at linaro.org> wrote:
> Hello,
>
> On the topic of C-state statistics:
>
> For 11.09 there are BP:s to A) fix powertop for ARM and B) create an
> Android app for running powertop in Android. By that I mean executing
> a reconfigured but upstreamable powertop as a service and control it
> from the app.
>
> I'd like input on usage patterns for powertop from all you PM experts
> in order to design that app as useful as possible. I'd imagine that
> the actual display (ncurses-based on other platforms) is cute and sure
> we should have it, but is it really that useful? Isn't the most
> important thing to get statistics between a starting and an ending
> time while some test or use case is executed?
>

Personally, I was using the --dump option for recording statistics
during a specific period. But i'm not sure if it's always available on
powertop 2.0

> So I am thinking that prio 1 is "tap to start/stop logging" and saving
> the set of result vectors for each measurement cycle to a file that
> can be taken out and processed off-line into a diagram or whatever.
>
> Other ideas?
>

The main problem with an android app is that you must have screen and
backlight on to use/configure it. Could it be possible to have an
option which start a record when android enters the early suspend
state ( with a additional delay to let the system stabilize) ? That
could be an interesting feature for what we call the low power use
case.

Vincent

> /Tony
>
>
>
> On 30 August 2011 10:09, Daniel Lezcano <daniel.lezcano at linaro.org> wrote:
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>>
>> Hi,
>>
>> I did some simple cpuidle measurements and updated the wiki page.
>>
>> https://wiki.linaro.org/WorkingGroups/PowerManagement/Doc/Cpuset
>>
>> Let me know what do you think about the result.
>>
>> Is there a way to get the C-states statistics ?
>>
>> Mike, you mentioned you did a very similar cpuset configuration but you
>> saw only a small improvement in term of power consumption, right ? Do
>> you have an idea why ?
>>
>> Thanks
>>  -- Daniel
>>
>> - --
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