From: Peter Zijlstra <peterz@infradead.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Arun Sharma <asharma@fb.com>,
avagin@gmail.com, linux-perf-users@vger.kernel.org,
acme@ghostprotocols.net, Stephane Eranian <eranian@google.com>,
Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: Profiling sleep times?
Date: Sat, 15 Oct 2011 21:29:19 +0200 [thread overview]
Message-ID: <1318706959.11898.1.camel@laptop> (raw)
In-Reply-To: <1318706522.2664.8.camel@laptop>
On Sat, 2011-10-15 at 21:22 +0200, Peter Zijlstra wrote:
> > Sleep time should really just be a different notion of 'cost of the
> > function/callchain' and fit into the existing scheme, right?
>
> The problem with andrew's patches is that it wrecks the callchain
> semantics. The waittime tracepoint is in the wakeup path (and hence
> generates the wakee's callchain) whereas they really want the callchain
> of the woken task to show where it spend time.
We could of course try to move the tracepoint into the schedule path, so
we issue it the first time the task gets scheduled after the wakeup, but
I suspect that will just add more overhead, and we really could do
without that.
next prev parent reply other threads:[~2011-10-15 19:29 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-03 19:38 Profiling sleep times? Arun Sharma
2011-10-03 20:17 ` Peter Zijlstra
2011-10-03 21:53 ` Arun Sharma
2011-10-04 8:34 ` Peter Zijlstra
2011-10-06 21:56 ` Arun Sharma
2011-10-07 0:05 ` Arun Sharma
2011-10-07 1:30 ` Peter Zijlstra
2011-10-07 5:42 ` avagin
2011-10-07 9:33 ` Peter Zijlstra
2011-10-07 17:58 ` Arun Sharma
2011-10-07 23:16 ` avagin
2011-10-08 1:45 ` avagin
2011-10-10 18:50 ` Arun Sharma
2011-10-12 7:41 ` Ingo Molnar
2011-10-13 5:39 ` Andrew Vagin
2011-10-14 21:19 ` Arun Sharma
2011-10-15 17:00 ` Ingo Molnar
2011-10-15 19:22 ` Peter Zijlstra
2011-10-15 19:29 ` Peter Zijlstra [this message]
2011-10-18 1:07 ` Arun Sharma
2011-10-22 10:49 ` Frederic Weisbecker
2011-10-22 16:22 ` Andrew Wagin
2011-10-23 0:27 ` Arun Sharma
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