[PATCH] perf: add OMAP support for the new power events

[Jean Pihet]

Hi Paul,

On Thu, Mar 10, 2011 at 2:04 AM, Paul Walmsley <paul at pwsan.com> wrote:
> On Thu, 3 Mar 2011, Jean Pihet wrote:
>
>> The patch adds the new power management trace points for
>> the OMAP architecture.
>>
>> The trace points are for:
>> - default idle handler. Since the cpuidle framework is
>>   instrumented in the generic way there is no need to
>>   add trace points in the OMAP specific cpuidle handler;
>> - cpufreq (DVFS),
>> - SoC clocks changes (enable, disable, set_rate),
>> - power domain states: the desired target state and -if different-
>>   the actually hit state.
>>
>> Because of the generic nature of the changes, OMAP3 and OMAP4 are supported.
>>
>> Tested on OMAP3 with suspend/resume, cpuidle, basic DVFS.
>>
>> Signed-off-by: Jean Pihet <j-pihet at ti.com>
>
> In terms of tracing powerdomain state changes, since OMAP powerdomains can
> potentially transition without the MPU knowing about it, some powerdomain
> transitions will be missed by these.  (The software counters miss them
> too.)  The only way to be certain about these is to watch the debug
> observability lines.  Still, it is the rare board that brings out debobs
> lines.  So this seems reasonable, as long as people don't expect 100%
> coverage.
OK that is correct. The events are tracing SW events only, i.e. a
trace is generated when a decision is made wrt next power states,
clock changes etc.
A remark: the OMAP4+ HW tracing modules do support the changes of
power domains states. There definitely is more to come on that topic!

Thanks for reviewing!
Jean

>
> For the clock and powerdomain changes,
>
> Acked-by: Paul Walmsley <paul at pwsan.com>
>
>
> - Paul
>