Re: [patch 00/10] [RFC] SLUB patches for more functionality,performance and maintenance

From: Christoph Lameter
Date: Mon Jul 09 2007 - 14:12:45 EST


On Mon, 9 Jul 2007, Martin Bligh wrote:

> Those numbers came from Mathieu Desnoyers (LTTng) if you
> want more details.

Okay the source for these numbers is in his paper for the OLS 2006: Volume
1 page 208-209? I do not see the exact number that you referred to there.

He seems to be comparing spinlock acquire / release vs. cmpxchg. So I
guess you got your material from somewhere else?

Also the cmpxchg used there is the lockless variant. cmpxchg 29 cycles w/o
lock prefix and 112 with lock prefix.

I see you reference another paper by Desnoyers:
http://tree.celinuxforum.org/CelfPubWiki/ELC2006Presentations?action=AttachFile&do=get&target=celf2006-desnoyers.pdf

I do not see anything relevant there. Where did those numbers come from?

The lockless cmpxchg is certainly an interesting idea. Certain for some
platforms I could disable preempt and then do a lockless cmpxchg.
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