From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Jiri Olsa <jolsa@kernel.org>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: perf,tools: Remove usage of trace_sched_wakeup(.success)
Date: Tue, 13 May 2014 19:14:36 +0200 [thread overview]
Message-ID: <20140513171436.GA8672@gmail.com> (raw)
In-Reply-To: <20140513100333.GW30445@twins.programming.kicks-ass.net>
* Peter Zijlstra <peterz@infradead.org> wrote:
> On Tue, May 13, 2014 at 03:34:32PM +0900, Dongsheng Yang wrote:
> > On 05/13/2014 04:22 PM, Ingo Molnar wrote:
> > >* Peter Zijlstra <peterz@infradead.org> wrote:
> > >
> > >>trace_sched_wakeup(.success) is a dead argument and has been for ages,
> > >Always 0, or random value?
> >
> > Hi Ingo,
> >
> > It is always 1 currently.
> >
> > Peter believe that .success is not useful and I pointed that perf
> > sched latency is using it now. Then he post this patch to remove
> > the usage here.
> >
> > Please go to the following link for more about this issue.
>
> It is _not_ usable. You're proposing to abuse the existing
> parameter. A wakeup doing an enqueue or not has nothing
> _WHAT_SO_EVER_ to do with success.
>
> Now what I think you wanted to do is make it easier to match
> trace_sched_switch() statements with trace_sched_wakeup()
> statements. And since you only get the trace_sched_switch() on
> dequeue, you want to know which trace_sched_wakeup() calls did an
> enqueue.
>
> But that's completely and utterly unrelated to success.
So I always considered it 'the enqueue was successful' - that's I
think why I added it to 'perf sched' originally - to be able to trace
wakeups from originator to target.
Thans,
Ingo
next prev parent reply other threads:[~2014-05-13 17:15 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-12 18:19 perf,tools: Remove usage of trace_sched_wakeup(.success) Peter Zijlstra
2014-05-13 1:38 ` [PATCH] perf_tools/sched: Remove nr_state_machine_bugs in perf latency Dongsheng Yang
2014-05-13 1:42 ` Dongsheng Yang
2014-05-13 11:56 ` Jiri Olsa
2014-05-19 11:59 ` Jiri Olsa
2014-05-21 9:25 ` Peter Zijlstra
2014-05-21 5:54 ` [tip:perf/core] perf sched: " tip-bot for Dongsheng Yang
2014-05-13 7:22 ` perf,tools: Remove usage of trace_sched_wakeup(.success) Ingo Molnar
2014-05-13 6:34 ` Dongsheng Yang
2014-05-13 10:03 ` Peter Zijlstra
2014-05-13 10:10 ` Dongsheng Yang
2014-05-13 11:26 ` Peter Zijlstra
2014-05-13 17:14 ` Ingo Molnar [this message]
2014-05-13 17:30 ` Peter Zijlstra
2014-05-13 18:15 ` Peter Zijlstra
2014-05-13 10:00 ` Peter Zijlstra
2014-05-21 5:54 ` [tip:perf/core] perf tools: Remove usage of trace_sched_wakeup( .success) tip-bot for Peter Zijlstra
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