Messages in this thread | | | Date | Fri, 3 Sep 2010 22:28:39 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] tracing, perf: add more power related events |
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* Thomas Renninger <trenn@suse.de> wrote:
> On Friday 03 September 2010 21:55:55 Ingo Molnar wrote: > > > > * Thomas Renninger <trenn@suse.de> 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
Ah, that wasnt in the first patch. (Please re-start discussion threads when something is re-submitted)
Nice website. Looks like these new tracepoints are really useful.
> There he shows the whole big patch and states:
Generally it's nice to post patches to lkml too, so that people have something to discuss.
> 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.
Yeah - but as long as they are at least attempted to be cross-platform, that would be fine. The ACPI folks are Cc:-ed so they can object if they dont like something.
> > - and check how existing tools like > > powertop make use of such events - and sync it all up. > > Does powertop use these events?
It certainly does quite a few things wrt. power usage analysis. Arjan is on the Cc:, maybe he has an opinion about these tracepoints.
> > 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.
Yeah, extensions rarely break anything. What i mentioned was 'inconsistent, architecture-dependent events', which is not a fact but a possible danger: as these new events are only for OMAP right now. They might be OK, they might be not OK - i dont know, that's why i suggested to make them cross-platform in practice too.
So it would be nice to get some feedback from the ACPI folks - but if you guys can also do an ACPI patch that would be even better!
Thanks,
Ingo
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