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From: Peter Zijlstra <peterz@infradead.org>
To: Alexander Gordeev <agordeev@redhat.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>,
	Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
	Jiri Olsa <jolsa@redhat.com>,
	Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH RFC -tip 0/6] perf: IRQ-bound performance events
Date: Tue, 4 Jun 2013 11:38:02 +0200	[thread overview]
Message-ID: <20130604093802.GK8923@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20130603133618.GK30878@dhcp-26-207.brq.redhat.com>

On Mon, Jun 03, 2013 at 03:36:19PM +0200, Alexander Gordeev wrote:
> On Mon, Jun 03, 2013 at 11:41:32AM +0200, Alexander Gordeev wrote:
> > # ./tools/perf/perf stat -I 8 -a -e L1-dcache-load-misses:k sleep 1
> > 
> >  Performance counter stats for process id '8':
> > 
> >                  0 L1-dcache-load-misses                                       
> > 
> >        1.001235781 seconds time elapsed
> > 
> > # ./tools/perf/perf stat -I 8 -a -e L1-dcache-load-misses:k hwclock --test
> > Mon 03 Jun 2013 04:42:59 AM EDT  -0.891274 seconds
> > 
> >  Performance counter stats for process id '8':
> 
> Oops, the most interesting part did not make it in. Very sorry :) Here:
> 
> # ./tools/perf/perf stat -I 8 -a -e L1-dcache-load-misses:k hwclock --test
> Mon 03 Jun 2013 09:32:49 AM EDT  -0.719514 seconds
> 
>  Performance counter stats for process id '8':
> 
>                447 L1-dcache-load-misses                                       

I think that is very much expected; except in the case where you spend
_all_ your time in IRQ handlers, they'll pretty much always miss l1
cache.

  reply	other threads:[~2013-06-04  9:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-03  9:41 [PATCH RFC -tip 0/6] perf: IRQ-bound performance events Alexander Gordeev
2013-06-03 12:22 ` Ingo Molnar
2013-06-03 19:41   ` Frederic Weisbecker
2013-06-04  8:51     ` Jiri Olsa
2013-06-03 13:36 ` Alexander Gordeev
2013-06-04  9:38   ` Peter Zijlstra [this message]
2013-06-04 10:14     ` Alexander Gordeev

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