Messages in this thread |  | | Date | Sun, 2 Aug 2009 22:13:21 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH][RFC] Adding transition of CPU frequency counting support to perfcounters |
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* Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp> wrote:
> From: Peter Zijlstra <a.p.zijlstra@chello.nl> > Subject: Re: [PATCH][RFC] Adding transition of CPU frequency counting support to perfcounters > Date: Sat, 18 Jul 2009 18:09:15 +0200 > > > On Sat, 2009-07-18 at 23:11 +0900, mitake@dcl.info.waseda.ac.jp wrote: > > > > > > Oh, my perf could count cpufreq events! > > > Thanks for your nice advice! > > > > > > % perf stat -a sleep 60 > > > > > > Performance counter stats for 'sleep 60': > > > > > > 479088.075595 task-clock-msecs # 7.984 CPUs > > > 199080 context-switches # 0.000 M/sec > > > 19584 CPU-migrations # 0.000 M/sec > > > 322978 page-faults # 0.001 M/sec > > > 29 cpufreq-up # 0.000 M/sec > > > 42 cpufreq-down # 0.000 M/sec > > > 73703367828 cycles # 153.841 M/sec > > > 52005203450 instructions # 0.706 IPC > > > 209762467 cache-references # 0.438 M/sec > > > 84916856 cache-misses # 0.177 M/sec > > > > > > 60.009508200 seconds time elapsed > > > > > > And I'm using ondemand governor now, > > > so kernel thread [kondemand] context causes freq transition. > > > I didn't notice that... > > > > > > Could you merge this patch? > > > Can I send this patch with descriptions and Signed-off-by? > > > > Why, what is the usecase? > > > > > > Hmm, I considered, and I noticed that this patch makes no sense. > Because my first purpose "collecting CPU freq transitions per > process level" is completely nonsense. CPU freq transitions are > global things, not one of processes.
Well, but 'perf stat -a' will install per CPU counters, i.e. the counting is global, not per task.
(even per task counting makes a certain amount of sense: which apps generate the most freq change events for example?)
Ingo
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