Re: [PATCH v5 1/3] perf/core: store context switch out type into Perf trace

From: Arnaldo Carvalho de Melo
Date: Mon Apr 16 2018 - 10:28:57 EST


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@xxxxxxxxxxxxxxx>
> >
> > Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> >
> > 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.
>
> Thanks,
> Alexey

Applying, rebuilding a kernel with this and testing,

- Arnaldo