lkml.org 
[lkml]   [2007]   [Mar]   [20]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
DateTue, 20 Mar 2007 08:39:30 +0100
FromEric Dumazet <>
SubjectRe: [PATCH] slab: deal with NULL pointers passed to kmem_cache_free
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.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-03-20 08:43    [from the cache]
©2003-2008