linux-kernel - Re: [PATCH 2/2] perf: Walk through the relevant events only

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Date:	Fri, 05 Mar 2010 10:39:29 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	LKML <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...e.hu>,
	Paul Mackerras <paulus@...ba.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Masami Hiramatsu <mhiramat@...hat.com>,
	Jason Baron <jbaron@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: Re: [PATCH 2/2] perf: Walk through the relevant events only

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].



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