From: Eric Dumazet <dada1@cosmosbay.com>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andrew Morton <akpm@linux-foundation.org>,
mpm@selenic.com, Christoph Lameter <clameter@sgi.com>,
"ast@domdv.de" <ast@domdv.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] slab: deal with NULL pointers passed to kmem_cache_free
Date: Tue, 20 Mar 2007 08:39:30 +0100 [thread overview]
Message-ID: <45FF8FB2.3060601@cosmosbay.com> (raw)
In-Reply-To: <84144f020703200014j1ec8a6feq9828fd8739beff18@mail.gmail.com>
Pekka Enberg a écrit :
> On 3/19/07, Andrew Morton <akpm@linux-foundation.org> wrote:
>> This is a super-hot path.
>
> Super-hot exactly where?
Don't be silly Pekka ... We have plenty oprofiles results if you dont trust
Andrew.
CPU: AMD64 processors, speed 1992.52 MHz (estimated)
Counted CPU_CLK_UNHALTED events (Cycles outside of halt state) with a unit
mask of 0x00 (No unit mask) count 100000
samples % symbol name
1861563 4.7882 tg3_start_xmit_dma_bug
1375727 3.5386 memcpy_c
1166438 3.0002 tcp_v4_rcv
1157334 2.9768 kmem_cache_free
In this workload (real server), you can see kmem_cache_free() is number four.
Adding one test and conditional branch in this super-hot function just to
correct a bug in a SCSI driver (or whatever) is not *SANE*.
Numbers talk.
next prev parent reply other threads:[~2007-03-20 7:40 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-19 8:27 [PATCH] slab: deal with NULL pointers passed to kmem_cache_free Pekka J Enberg
2007-03-19 11:31 ` Andrew Morton
2007-03-19 11:40 ` Pekka J Enberg
2007-03-19 17:08 ` Christoph Lameter
2007-03-19 17:31 ` Pekka J Enberg
2007-03-19 20:49 ` Matt Mackall
2007-03-19 21:10 ` Andrew Morton
2007-03-19 21:25 ` Pekka Enberg
2007-03-19 21:41 ` Andrew Morton
2007-03-19 21:49 ` Matt Mackall
2007-03-20 7:06 ` Pekka Enberg
2007-03-20 18:41 ` Christoph Lameter
2007-03-21 11:42 ` Pekka J Enberg
2007-03-20 7:14 ` Pekka Enberg
2007-03-20 7:39 ` Eric Dumazet [this message]
2007-03-20 7:47 ` Pekka J Enberg
2007-03-20 7:56 ` Eric Dumazet
2007-03-21 10:11 ` Jarek Poplawski
2007-03-21 12:13 ` Pekka Enberg
2007-03-21 13:31 ` Jarek Poplawski
2007-03-21 13:36 ` Pekka J Enberg
2007-03-21 14:11 ` Rafael J. Wysocki
2007-03-21 14:41 ` Pekka Enberg
2007-03-21 16:30 ` Andrew Morton
2007-03-21 17:54 ` Jörn Engel
2007-03-21 18:32 ` Pekka Enberg
2007-03-21 14:45 ` Jarek Poplawski
2007-03-19 22:04 ` Jörn Engel
2007-03-19 21:16 ` Christoph Lameter
2007-03-19 21:44 ` Matt Mackall
2007-03-19 23:32 ` Andreas Steinmetz
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