From: Ingo Molnar <mingo@elte.hu>
To: "Mike Galbraith" <efault@gmx.de>,
"Arnaldo Carvalho de Melo" <acme@redhat.com>,
"Frédéric Weisbecker" <fweisbec@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [patch] perf_counter tools: remove expensive old debug code from perf top
Date: Tue, 13 Oct 2009 15:37:07 +0200 [thread overview]
Message-ID: <20091013133707.GA21409@elte.hu> (raw)
In-Reply-To: <1255438640.7173.1.camel@marge.simson.net>
* Mike Galbraith <efault@gmx.de> wrote:
> perf_counter tools: remove expensive old debug code from perf top
>
> Calling gettimeofday() at high frequency is painful for handicapped
> boxen. The spot calling gettimeofday() is old unneeded debug code, so
> remove it.
Thanks!
We still seem to have a performance problem. Just running perf top on a
16-way box:
Performance counter stats for 'perf top -e cycles -c 3000000':
585.694831 task-clock-msecs # 0.113 CPUs
35163 context-switches # 0.060 M/sec
17 CPU-migrations # 0.000 M/sec
20355 page-faults # 0.035 M/sec
1476952962 cycles # 2521.711 M/sec
730770658 instructions # 0.495 IPC
11489471 cache-references # 19.617 M/sec
2055001 cache-misses # 3.509 M/sec
5.169518576 seconds time elapsed
that's 11% of CPU time used on a single CPU - just displaying a measly
16K irqs/sec. Something's not quite right here.
Ingo
next prev parent reply other threads:[~2009-10-13 13:37 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-13 12:57 [patch] perf_counter tools: remove expensive old debug code from perf top Mike Galbraith
2009-10-13 13:34 ` [tip:perf/core] perf tools: Remove " tip-bot for Mike Galbraith
2009-10-13 13:37 ` Ingo Molnar [this message]
2009-10-13 14:41 ` [patch] perf_counter tools: remove " Mike Galbraith
2009-10-13 14:43 ` Arnaldo Carvalho de Melo
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