linux-kernel - Re: [PATCH 00/15] various perf counter bits

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Message-ID: <20090407092333.GB17301@elte.hu>
Date:	Tue, 7 Apr 2009 11:23:33 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:	Paul Mackerras <paulus@...ba.org>,
	Corey Ashford <cjashfor@...ux.vnet.ibm.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 00/15] various perf counter bits


another thing i noticed is that our CPU migration counters look a 
bit weird:

aldebaran:~/linux/linux/Documentation/perf_counter> taskset 1 perfstat ls
design.txt  kerneltop  kerneltop.c  Makefile  perfstat

 Performance counter stats for 'ls':

       0.686802  task clock ticks     (msecs)
              3  context switches     (events)
              4  CPU migrations       (events)
            285  pagefaults           (events)
        2183899  CPU cycles           (events)
        1492516  instructions         (events)
          24638  cache references     (events)
           1763  cache misses         (events)

 Wall-clock time elapsed:     0.694796 msecs


the 'taskset 1' binds perfstat to a single CPU - still we had 4 
cross-CPU migrations?

	Ingo
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