Re: [PATCH] tracing, perf: add more power related events

[Thomas Renninger]

On Friday 03 September 2010 21:55:55 Ingo Molnar wrote:
> 
> * Thomas Renninger <trenn@xxxxxxx> wrote:
> 
> > Hi Jean,
> > 
> > Summary at the beginning if people stop reading on the details
> > below...:
> > Nice work!
> > You have my vote to get this merged.
> > I think it's up to Ingo to push it.
> 
> Well, the patch that got posted:
> 
>   [PATCH] tracing, perf: add more power related events
> 
> Only adds tracepoints to power.h, but doesnt actually use them anywhere 
> ...
> 
> Is there a companion patch i missed?
Yep.
Jean has nicely made up a tiny website he refered to in his mail:
http://www.omappedia.com/wiki/Power_Management_Debug_and_Profiling
There he shows the whole big patch and states:
Since the patch touches generic files (in include/trace/events/power.h), it is split in parts:
    * generic code: submitted to the LKML, cf. http://marc.info/?l=linux-kernel&m=128195697205096&w=4 ,
    * ARM/OMAP specific code for the already existing events: to be submitted to l-o, cf. http://www.spinics.net/lists/linux-omap/msg35357.html,
    * ARM/OMAP specific code for the new events, to be submitted once the generic code is accepted. 

> Also, it would be nice to add it to x86 and to OMAP at once, and 
> synchronize up all the power events
I can add sleep state events to x86 acpi parts, but even these are, as said, not
that interesting as they might be on ARM ultra mobile use cases.

> - and check how existing tools like 
> powertop make use of such events - and sync it all up.
Does powertop use these events?

> We dont want to 
> have inconsistent, architecture-dependent events in the end, for obvious 
> reasons.
Jean also shows screenshots at the link above
how perf timechart or the the corresponding
gui app PyTimechart still works together with these.
I can't see how the new events should break an existing app, they should
just ignore events they are not aware of.

     Thomas
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