From: Andi Kleen <andi@firstfloor.org>
To: Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
Cc: Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH][RFC] Adding information of counts processes acquired how many spinlocks to schedstat
Date: Wed, 01 Jul 2009 09:38:04 +0200 [thread overview]
Message-ID: <87hbxwj1k3.fsf@basil.nowhere.org> (raw)
In-Reply-To: <20090701.152115.706994265076015808.mitake@dcl.info.waseda.ac.jp> (Hitoshi Mitake's message of "Wed, 01 Jul 2009 15:21:15 +0900 (JST)")
Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp> writes:
> Hi,
>
> I wrote a test patch which add information of counts processes acquired how many spinlocks to schedstat.
> After applied this patch, /proc/<PID>/sched will change like this,
The problem is that spinlocks are very common and schedstats is enabled commonly
in production kernels. You would need to demonstrate that such a change doesn't
have significant performance impact. For me it looks like it has.
Also I'm not sure exactly what good such a metric is. Do you have
a concrete use case?
The normal way to check for lock contention or lock bouncingis to
simply profile cycles or time and see if there is a lot of CPU time in
locks.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2009-07-01 7:38 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-01 6:21 [PATCH][RFC] Adding information of counts processes acquired how many spinlocks to schedstat Hitoshi Mitake
2009-07-01 7:31 ` Ingo Molnar
2009-07-01 8:21 ` Hitoshi Mitake
2009-07-01 13:45 ` Frederic Weisbecker
2009-07-01 13:50 ` Ingo Molnar
2009-07-01 14:17 ` mitake
2009-07-01 7:38 ` Andi Kleen [this message]
2009-07-01 8:42 ` Hitoshi Mitake
2009-07-01 9:07 ` Ingo Molnar
2009-07-01 9:42 ` Hitoshi Mitake
2009-07-01 11:06 ` Ingo Molnar
2009-07-01 12:53 ` Hitoshi Mitake
2009-07-01 15:44 ` Frederic Weisbecker
2009-07-06 5:20 ` mitake
2009-07-06 8:51 ` Peter Zijlstra
2009-07-06 11:54 ` Andi Kleen
2009-07-10 12:45 ` mitake
2009-07-10 12:52 ` Peter Zijlstra
2009-07-10 13:43 ` Ingo Molnar
2009-07-10 13:46 ` Frederic Weisbecker
2009-07-10 13:50 ` Ingo Molnar
2009-07-10 13:56 ` Peter Zijlstra
2009-07-12 7:23 ` Hitoshi Mitake
2009-07-12 13:24 ` Peter Zijlstra
2009-07-13 6:06 ` Hitoshi Mitake
2009-07-13 8:51 ` Ingo Molnar
2009-07-14 0:48 ` Hitoshi Mitake
2009-07-18 13:25 ` Ingo Molnar
2009-07-01 12:40 ` Andi Kleen
2009-07-01 13:50 ` [PATCH][RFC] Adding information of counts processes acquired how many spinlocks to schedstat II Andi Kleen
2009-07-01 9:48 ` [PATCH][RFC] Adding information of counts processes acquired how many spinlocks to schedstat Andi Kleen
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