From: David Miller <davem@davemloft.net>
To: clameter@sgi.com
Cc: linux-kernel@vger.kernel.org, linux-mm@vger.kernel.org,
suresh.b.siddha@intel.com, corey.d.gough@intel.com,
penberg@cs.helsinki.fi, akpm@linux-foundation.org
Subject: Re: [patch 00/10] [RFC] SLUB patches for more functionality, performance and maintenance
Date: Mon, 09 Jul 2007 12:43:59 -0700 (PDT) [thread overview]
Message-ID: <20070709.124359.38710002.davem@davemloft.net> (raw)
In-Reply-To: <Pine.LNX.4.64.0707090845230.13792@schroedinger.engr.sgi.com>
From: Christoph Lameter <clameter@sgi.com>
Date: Mon, 9 Jul 2007 08:45:42 -0700 (PDT)
> On Sat, 7 Jul 2007, David Miller wrote:
>
> > From: Christoph Lameter <clameter@sgi.com>
> > Date: Sat, 07 Jul 2007 20:49:52 -0700
> >
> > > A cmpxchg is less costly than interrupt enabe/disable
> >
> > This is cpu dependant, and in fact not true at all on Niagara
> > and several of the cpus in the UltraSPARC family.
>
> Hmmm... So have alternate aloc/free paths depending on the cpu?
As Andi seemed to imply I don't even think cmpxchg is faster than
interrupt enable/disable on current generation AMD x86_64 chips, so
are you targetting this optimization solely at Intel x86 Core Duo
32-bit chips? That's the only one I can see which will benefit from
this. Are you going to probe the cpu sub-type and patch SLUB?
I really don't think this optimization is wise as even if you
could decide at build time, it's going to be a maintainence and
debugging nightmare to have to field bug reports given two different
locking schemes.
Please reconsider this change, thanks.
next prev parent reply other threads:[~2007-07-09 19:43 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-08 3:49 [patch 00/10] [RFC] SLUB patches for more functionality, performance and maintenance Christoph Lameter
2007-07-08 3:49 ` [patch 01/10] SLUB: Direct pass through of page size or higher kmalloc requests Christoph Lameter
2007-07-08 3:49 ` [patch 02/10] SLUB: Avoid page struct cacheline bouncing due to remote frees to cpu slab Christoph Lameter
2007-07-08 3:49 ` [patch 03/10] SLUB: Do not use page->mapping Christoph Lameter
2007-07-08 3:49 ` [patch 04/10] SLUB: Move page->offset to kmem_cache_cpu->offset Christoph Lameter
2007-07-08 3:49 ` [patch 05/10] SLUB: Avoid touching page struct when freeing to per cpu slab Christoph Lameter
2007-07-08 3:49 ` [patch 06/10] SLUB: Place kmem_cache_cpu structures in a NUMA aware way Christoph Lameter
2007-07-08 3:49 ` [patch 07/10] SLUB: Optimize cacheline use for zeroing Christoph Lameter
2007-07-08 3:50 ` [patch 08/10] SLUB: Single atomic instruction alloc/free using cmpxchg Christoph Lameter
2007-07-08 3:50 ` [patch 09/10] Remove the SLOB allocator for 2.6.23 Christoph Lameter
2007-07-08 7:51 ` Ingo Molnar
2007-07-08 9:43 ` Nick Piggin
2007-07-08 9:54 ` Ingo Molnar
2007-07-08 10:23 ` Nick Piggin
2007-07-08 10:42 ` Ingo Molnar
2007-07-08 18:02 ` Andrew Morton
2007-07-09 2:57 ` Nick Piggin
2007-07-09 11:04 ` Pekka Enberg
2007-07-09 11:16 ` Nick Piggin
2007-07-09 12:47 ` Pekka Enberg
2007-07-09 13:46 ` Pekka J Enberg
2007-07-09 16:08 ` Christoph Lameter
2007-07-10 8:17 ` Pekka J Enberg
2007-07-10 8:27 ` Nick Piggin
2007-07-10 9:31 ` Pekka Enberg
2007-07-10 10:09 ` Nick Piggin
2007-07-10 12:02 ` Matt Mackall
2007-07-10 12:57 ` Pekka J Enberg
2007-07-10 22:12 ` Christoph Lameter
2007-07-10 22:40 ` Matt Mackall
2007-07-10 22:50 ` Christoph Lameter
2007-07-09 16:06 ` Christoph Lameter
2007-07-09 16:51 ` Andrew Morton
2007-07-09 17:26 ` Christoph Lameter
2007-07-09 18:00 ` Andrew Morton
2007-07-10 1:43 ` Nick Piggin
2007-07-10 1:56 ` Christoph Lameter
2007-07-10 2:02 ` Nick Piggin
2007-07-10 2:11 ` Christoph Lameter
2007-07-10 7:09 ` Nick Piggin
2007-07-10 22:09 ` Christoph Lameter
2007-07-10 23:12 ` Matt Mackall
2007-07-10 8:32 ` Matt Mackall
2007-07-10 9:01 ` Håvard Skinnemoen
2007-07-10 9:11 ` Nick Piggin
2007-07-10 9:21 ` Håvard Skinnemoen
2007-07-11 1:37 ` Christoph Lameter
2007-07-11 2:06 ` Matt Mackall
2007-07-11 18:06 ` Christoph Lameter
2007-07-11 18:25 ` Pekka J Enberg
2007-07-11 18:33 ` Christoph Lameter
2007-07-11 18:36 ` Pekka J Enberg
2007-07-12 0:33 ` Nick Piggin
2007-07-09 23:09 ` Matt Mackall
2007-07-10 1:41 ` Nick Piggin
2007-07-10 1:51 ` Christoph Lameter
2007-07-10 1:58 ` Nick Piggin
2007-07-10 6:22 ` Matt Mackall
2007-07-10 7:03 ` Nick Piggin
2007-07-10 2:32 ` Matt Mackall
2007-07-09 21:57 ` Matt Mackall
2007-07-09 12:31 ` Matthieu CASTET
2007-07-09 16:00 ` Christoph Lameter
2007-07-09 20:52 ` Matt Mackall
2007-07-08 3:50 ` [patch 10/10] Remove slab in 2.6.24 Christoph Lameter
2007-07-08 4:37 ` [patch 00/10] [RFC] SLUB patches for more functionality, performance and maintenance David Miller
2007-07-09 15:45 ` Christoph Lameter
2007-07-09 19:43 ` David Miller [this message]
2007-07-09 21:21 ` Christoph Lameter
2007-07-08 11:20 ` Andi Kleen
2007-07-09 15:50 ` Christoph Lameter
2007-07-09 15:59 ` Martin Bligh
2007-07-09 18:11 ` Christoph Lameter
2007-07-09 21:00 ` Martin Bligh
2007-07-09 21:44 ` Mathieu Desnoyers
2007-07-09 21:55 ` Christoph Lameter
2007-07-09 22:58 ` Mathieu Desnoyers
2007-07-09 23:08 ` Christoph Lameter
2007-07-10 5:16 ` [PATCH] x86_64 - Use non locked version for local_cmpxchg() Mathieu Desnoyers
2007-07-10 20:46 ` Christoph Lameter
2007-07-10 0:55 ` [patch 00/10] [RFC] SLUB patches for more functionality, performance and maintenance Christoph Lameter
2007-07-10 8:27 ` Mathieu Desnoyers
2007-07-10 18:38 ` Christoph Lameter
2007-07-10 20:59 ` Mathieu Desnoyers
2007-08-13 22:18 ` Mathieu Desnoyers
2007-08-13 22:28 ` Christoph Lameter
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