From: Andi Kleen <andi@firstfloor.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: mitake@dcl.info.waseda.ac.jp, fweisbec@gmail.com, mingo@elte.hu,
acme@redhat.com, andi@firstfloor.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH][RFC] Adding information of counts processes acquired how many spinlocks to schedstat
Date: Mon, 6 Jul 2009 13:54:51 +0200 [thread overview]
Message-ID: <20090706115451.GA29715@one.firstfloor.org> (raw)
In-Reply-To: <1246870279.8143.4.camel@twins>
> Maybe re-use the LOCK_CONTENDED macros for this, but I'm not sure we
> want to go there and put code like this on the lock hot-paths for !debug
> kernels.
My concern was similar.
I suspect it would be in theory ok for the slow spinning path, but I am
somewhat concerned about the additional cache miss for checking
the global flag even in this case. This could hurt when
the kernel is running fully cache hold, in that the cache miss
might be far more expensive that short spin.
Needs immediate value patching or just use a jumper kprobe when it's
really needed? I think I would prefer the later variant.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2009-07-06 11:54 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
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 [this message]
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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