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author | Peter Zijlstra <peterz@infradead.org> | 2015-04-17 20:05:30 +0200 |
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committer | Ingo Molnar <mingo@kernel.org> | 2015-05-08 12:25:38 +0200 |
commit | ff303e66c240ba6269e31817a386995440a18c99 (patch) | |
tree | aa4e506beabc409966d9cda0c722dee41e8d8ce9 /init | |
parent | 1836ac856e4fb446e48afa4f8cae897d4856b06c (diff) | |
download | linux-ff303e66c240ba6269e31817a386995440a18c99.tar.gz linux-ff303e66c240ba6269e31817a386995440a18c99.tar.bz2 linux-ff303e66c240ba6269e31817a386995440a18c99.zip |
perf: Fix software migrate events
Stephane asked about PERF_COUNT_SW_CPU_MIGRATIONS and I realized it
was borken:
> The problem is that the task isn't actually scheduled while its being
> migrated (obviously), and if its not scheduled, the counters aren't
> scheduled either, so there's no observing of the fact.
>
> A further problem with migrations is that many migrations happen from
> softirq context, which is nested inside the 'random' task context of
> whoemever happens to run at that time, similarly for the wakeup
> migrations triggered from (soft)irq context. All those end up being
> accounted in the task that's currently running, eg. your 'ls'.
The below cures this by marking a task as migrated and accounting it
on the subsequent sched_in().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'init')
0 files changed, 0 insertions, 0 deletions