Messages in this thread | | | Subject | Re: [RFC PATCH 0/3] perf: show package power consumption in perf | From | Lin Ming <> | Date | Thu, 19 Aug 2010 11:28:17 +0800 |
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On Wed, 2010-08-18 at 20:41 +0800, Matt Fleming wrote: > On Wed, Aug 18, 2010 at 02:25:29PM +0200, Peter Zijlstra wrote: > > On Wed, 2010-08-18 at 15:59 +0800, Zhang Rui wrote: > > > Hi, all, > > > > > > RAPL(running average power limit) is a new feature which provides > > > mechanisms to enforce power consumption limit, on some new processors. > > > > > > Generally speaking, by using RAPL, OS can set a power budget in a > > > certain time window, and let Hardware to throttle the processor > > > P/T-state to meet this energy limitation. > > > > > > RAPL also provides a new MSR, i.e. MSR_PKG_ENERGY_STATUS, which reports > > > the total amount of energy consumed by the package. > > > > > > I'm not sure if to support RAPL or not, but anyway, it sounds like a > > > good idea to export the energy status in perf. > > > > > > So a new perf pmu and event to show the package energy consumed is > > > introduced in this patch. > > > > > > Here is what I get after applying the three patches, > > > > > > #./perf stat -e energy test > > > Performance counter stats for 'test': > > > > > > 202 Joules cost by package > > > 7.926001238 seconds time elapsed > > > > > > > > > Note that this patch set is made based on Peter's perf-pmu branch, > > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/linux-2.6-perf.git > > > which provides better interfaces to register/unregister a new pmu. > > > > > > any comment are welcome. :) > > > > > > Nice,.. however: > > > > - if it is a pure read-only counter without sampling support, > > expose it as such, don't fudge in the hrtimer stuff. Simply > > fail to create a sampling event. > > > > SH has the same problem for its 'normal' PMU, the solution is > > to use event groups, Matt was looking at adding support to > > perf-record for that, if creating a sampling event fails, fall > > back to {hrtimer, $event} groups. > > I had a quick look over the patches and Peter is right - the group > events stuff would probably fit quite well here. Unfortunately, due to > holidays and things, I haven't been able to get them finished > yet. I'll get on that ASAP.
Hi, Matt
What's the "group events stuff"? Is there some discussion on LKML or elsewhere I can have a look at?
Thanks, Lin Ming
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