Re: [PATCH 3/4] perf: teach perf inject to merge sched_stat_* and sched_switch events (v2)

From: Andi Kleen
Date: Mon Aug 27 2012 - 18:14:20 EST


On Mon, Aug 27, 2012 at 03:56:23PM -0600, David Ahern wrote:
> On 8/27/12 2:51 PM, Andi Kleen wrote:
> >Andrew Vagin <avagin@xxxxxxxxxx> writes:
> >>
> >>My code saves sched_switch event for each process and when it meets
> >>stat_iowait, it reports the sched_switch event, because this event
> >>contains a correct callchain. By another words it replaces all
> >>stat_iowait events on proper sched_switch events.
> >
> >Is there any way to generalize this to arbitary events? I found myself
> >writing scripts to compute lengths between various events. But I
>
> You mean delta-time between events? I have toyed around with patches to
> perf-script for this -- dt between same event on a cpu, dt between
> consecutive events on a cpu, dt between events for a thread, etc.

I did the same. But I then realized perf script is the wrong approach.
perf script is a deadend as far as perf is concerned.
You want a filter that generates another perf.data that you then can
view in the browser. So perf inject is the better model.

-Andi
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