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Message-ID: <1342017499.3462.160.camel@twins>
Subject: Re: [PATCH] trace: add ability to set a target task for events (v2)
From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Vagin <avagin@openvz.org>, linux-kernel@vger.kernel.org,
        Ingo Molnar <mingo@kernel.org>, Steven Rostedt <rostedt@goodmis.org>,
        Paul Mackerras <paulus@samba.org>,
        Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
        Arun Sharma <asharma@fb.com>
Date: Wed, 11 Jul 2012 16:38:19 +0200
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On Wed, 2012-07-11 at 16:36 +0200, Frederic Weisbecker wrote:
> 
> In this case he can just record sched wakeup as well. With sched_switch
> + sched_wakeup, he'll unlikely lose events.
> 
> With sched_stat_sleep he will lose events, unless we fix this period
> demux thing. 

But without this patch, the sched_wakeup will belong to another task, so
if you trace task A, and B wakes you, you'll never see the wakeup.