Messages in this thread |  | | Date | Mon, 16 Apr 2018 10:59:57 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH v5 1/3] perf/core: store context switch out type into Perf trace |
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Em Mon, Apr 16, 2018 at 11:29:03AM +0300, Alexey Budankov escreveu: > Hi Arnaldo, > > On 09.04.2018 12:26, Peter Zijlstra wrote: > > On Mon, Apr 09, 2018 at 10:25:32AM +0300, Alexey Budankov wrote: > >> > >> Store preempting context switch out event into Perf trace as a part of > >> PERF_RECORD_SWITCH[_CPU_WIDE] record. > >> > >> Percentage of preempting and non-preempting context switches help > >> understanding the nature of workloads (CPU or IO bound) that are running > >> on a machine; > >> > >> The event is treated as preemption one when task->state value of the > >> thread being switched out is TASK_RUNNING. Event type encoding is > >> implemented using PERF_RECORD_MISC_SWITCH_OUT_PREEMPT bit; > >> > >> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> > > > > Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> > > > > Acme, I'm thinking you should route this, since most of the changes are > > actually to the tool. > > This is just to make sure it doesn't sneak out of your attention > in hope the plan is still the same as Peter mentioned above.
Will look into this now.
> Thanks, > Alexey > > > > >> diff --git a/kernel/events/core.c b/kernel/events/core.c > >> index fc1c330c6bd6..872a5aaa77eb 100644 > >> --- a/kernel/events/core.c > >> +++ b/kernel/events/core.c > >> @@ -7584,6 +7584,10 @@ static void perf_event_switch(struct task_struct *task, > >> }, > >> }; > >> > >> + if (!sched_in && task->state == TASK_RUNNING) > >> + switch_event.event_id.header.misc |= > >> + PERF_RECORD_MISC_SWITCH_OUT_PREEMPT; > > > > I typically prefer {} over any multi-line expression. > > > >> perf_iterate_sb(perf_event_switch_output, > >> &switch_event, > >> NULL); > >
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