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Subject: Re: [PATCH 2/2] perf: Walk through the relevant events only
From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
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       Arnaldo Carvalho de Melo <acme@redhat.com>
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Date: Fri, 05 Mar 2010 10:39:29 +0100
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On Fri, 2010-03-05 at 08:00 +0100, Frederic Weisbecker wrote:
> Each time a trace event triggers, we walk through the entire
> list of events from the active contexts to find the perf events
> that match the current one.
> 
> This is wasteful. To solve this, we maintain a per cpu list of
> the active perf events for each running trace events and we
> directly commit to these.

Right, so this seems a little trace specific. I once thought about using
a hash table to do this for all software events. It also keeps it all
nicely inside perf_event.[ch].