On Tuesday 21 June 2011 03:12 AM, Benjamin Herrenschmidt wrote: > On Mon, 2011-06-20 at 22:48 +0530, deepthi wrote: >> On Friday 17 June 2011 09:54 AM, Benjamin Herrenschmidt wrote: >>> On Wed, 2011-06-01 at 18:05 +0530, Deepthi Dharwar wrote: >>>> Hi, >>>> >>>> Please find below a patch, which has perf_events added for pseries (ppc64) >>>> platform in order to emit the trace required for perf timechart. >>>> It essentially enables perf timechart for pseries platfrom to analyse >>>> power savings events like cpuidle states. >>> >>> Unless I'm mistaken, you added traces to dedicated CPU idle sleep but >>> not shared processor. Any reason ? >>> >> Yes, the traces were added only to dedicated CPU idle sleep and not for >> shared processor. This was added only for RFC purpose, and looking for >> comments from trace implementation point of view. This can be >> easily extended to the latter too. > > Please do both. > Yes, I ll do so. >>> Also I don't really know that tracing stuff but what's the point of >>> having start/end _and trace_cpu_idle if you're going to always start & >>> end around a single occurence of trace_cpu_idle ? >>> >> power_start/end are the APIs that were used initially >> and they are going to be deprecated in the upcoming kernel releases. >> trace_cpu_idle call is going to replace power start/end routines. >> To maintain backward compatibility and uniformity, both the routines >> have been used. >> (ref:https://lkml.org/lkml/2010/11/14/60ref:https://lkml.org/lkml/2010/11/14/60) > > Backward compatible with what ? Userspace ? Do we care in that specific > case since it's a new feature ? > Going forward, we can just have trace_cpu_idle call and remove the power_start/end calls. >>> Wouldn't there be a way to start/end and then trace the snooze and >>> subsequent cede within the same start/end section or that makes no >>> sense ? >>> >> We wanted to find the residency time of both Snooze as well as cede >> separately. Knowing this will help us tweak our cpuidle code. So, both >> have been captured separately. >> >>> Also would there be any interest in doing the tracing more generically >>> in idle.c ? >>> >> Yes, this tracing is already implemented for Intel platform. This would >> be a part of cpuidle framework. Going further, once the power cpuidle >> framework is ported and ready, we will extend this trace there as well. >> (ref:https://lkml.org/lkml/2011/6/7/375) > > So do we need to apply this patch at all since the cpuidle stuff is > happening too ? > Well, not really. This is more for RFC purpose. I just wanted to share this patch, as we are using it to evaluate cpu idle on ppc64. > Cheers, > Ben. > > > _______________________________________________ > Linuxppc-dev mailing list > Linuxppc-dev@xxxxxxxxxxxxxxxx > https://lists.ozlabs.org/listinfo/linuxppc-dev _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
