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Date: Thu, 10 Jun 2010 08:26:18 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Arnaldo Carvalho de Melo <acme@redhat.com>,
       Paul Mackerras <paulus@samba.org>,
       Stephane Eranian <eranian@google.com>,
       Cyrill Gorcunov <gorcunov@gmail.com>,
       Zhang Yanmin <yanmin_zhang@linux.intel.com>,
       Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH 0/5] perf events finer grained context instrumentation /
 context exclusion
Message-ID: <20100610062618.GA20062@elte.hu>
References: <1276141760-11590-1-git-send-regression-fweisbec@gmail.com>
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:

> Here is the new version of per context exclusion, based on hooks on 
> irq_enter/irq_exit. I haven't observed slowdowns but I haven't actually 
> measured the impact.

One thing that would be nice to see in this discussion is a comparison of 
before/after perf stat --repeat runs.

Something like:

  perf stat --repeat ./hackbench 5

Done with full stat, and then also done with hardirqs/softirqs excluded. (i.e. 
task context stats only)

I.e. does the feature really give us the expected statistical stability in 
results? Does it really exclude hardirq/softirq workloads, etc.?

Thanks,

	Ingo