From: Manfred Spraul <manfred@colorfullife.com>
To: "Scott L. Burson" <gyro@zeta-soft.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: SMP performance problem in 2.4 (was: Athlon spinlock performance)
Date: Wed, 06 Aug 2003 19:21:15 +0200 [thread overview]
Message-ID: <3F31390B.2000605@colorfullife.com> (raw)
Scott wrote:
>The problem is in `try_to_free_pages' and its associated routines,
>`shrink_caches' and `shrink_cache', in `mm/vmscan.c'. After I made some
>changes to greatly reduce lock contention in the slab allocator and
>`shrink_cache',
>
How did you change the slab locking?
> and then instrumented `shrink_cache' to see what it was
>doing, the problem showed up very clearly.
>
>In one approximately 60-second period with the problematic workload running,
>`try_to_free_pages' was called 511 times. It made 2597 calls to
>`shrink_caches', which made 2592 calls to `shrink_cache' (i.e. it was very
>rare for `kmem_cache_reap' to release enough pages itself).
>
2.6 contains a simple fix: I've removed kmem_cache_reap. Instead the
code checks for empty pages in the slab caches every other second.
--
Manfred
next reply other threads:[~2003-08-06 17:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-06 17:21 Manfred Spraul [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-08-02 20:03 SMP performance problem in 2.4 (was: Athlon spinlock performance) Scott L. Burson
2003-08-02 21:44 ` Andrew Morton
2003-08-03 10:00 ` Scott L. Burson
2003-08-06 2:37 ` Rik van Riel
2003-08-03 2:40 ` Rik van Riel
2003-08-03 5:18 ` Con Kolivas
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