From: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
Date: Thu, 18 Mar 2010 14:36:04 +0000 (-0300)
Subject: perf record: Enable counters only when kernel is execing subcommand
X-Git-Tag: v2.6.35-rc1~522^2~172
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=46be604b5ba738d53e5f5314813a4e7092864baf;p=pandora-kernel.git

perf record: Enable counters only when kernel is execing subcommand

'perf record' starts counters before subcommand is execed, so
the statistics is not precise because it includes data of some
preparation steps. I fix it with the patch.

In addition, change the condition to fork/exec subcommand. If
there is a subcommand parameter, perf always fork/exec it. The
usage example is:

 # perf record -f -a sleep 10

So this command could collect statistics for 10 seconds
precisely. User still could stop it by CTRL+C. Without the new
capability, user could only input CTRL+C to stop it without
precise time clock.

Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sheng Yang <sheng@linux.intel.com>
Cc: oerg Roedel <joro@8bytes.org>
Cc: Jes Sorensen <Jes.Sorensen@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: <zhiteng.huang@intel.com>
Cc: Zachary Amsden <zamsden@redhat.com>
LKML-Reference: <1268922965-14774-2-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

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