From: Peter Zijlstra <peterz@infradead.org>
Date: Wed, 12 Nov 2014 11:37:37 +0000 (+0100)
Subject: sched/cputime: Fix cpu_timer_sample_group() double accounting
X-Git-Tag: omap-for-v3.19/fixes-for-merge-window~94^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=23cfa361f3e54a3e184a5e126bbbdd95f984881a;p=pandora-kernel.git

sched/cputime: Fix cpu_timer_sample_group() double accounting

While looking over the cpu-timer code I found that we appear to add
the delta for the calling task twice, through:

  cpu_timer_sample_group()
    thread_group_cputimer()
      thread_group_cputime()
        times->sum_exec_runtime += task_sched_runtime();

    *sample = cputime.sum_exec_runtime + task_delta_exec();

Which would make the sample run ahead, making the sleep short.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20141112113737.GI10476@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

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