lkml.org 
[lkml]   [2003]   [Aug]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: SMP performance problem in 2.4 (was: Athlon spinlock performance)
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

-
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: 2005-03-22 13:47    [W:0.039 / U:0.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site