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. > > 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 ? > > 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 ? Cheers, Ben. _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
