linux-kernel - Re: [this_cpu_xx V7 0/8] Per cpu atomics in core allocators and cleanup

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Date:	Thu, 17 Dec 2009 19:13:58 -0500
From:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
To:	Christoph Lameter <cl@...ux-foundation.org>
Cc:	Tejun Heo <tj@...nel.org>, linux-kernel@...r.kernel.org,
	Mel Gorman <mel@....ul.ie>,
	Pekka Enberg <penberg@...helsinki.fi>,
	Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [this_cpu_xx V7 0/8] Per cpu atomics in core allocators and
	cleanup

* Christoph Lameter (cl@...ux-foundation.org) wrote:
> On Thu, 17 Dec 2009, Mathieu Desnoyers wrote:
> 
> > Some quick test on my Intel Xeon E5405:
> >
> > local cmpxchg:  14 cycles
> > xchg:           18 cycles
> >
> > So yes, indeed, the non-LOCK prefixed local cmpxchg seems a bit faster
> > than the xchg, given the latter has an implied LOCK prefix.
> >
> > Code used for local cmpxchg:
> >                 old = var;
> >                 do {
> >                         ret = cmpxchg_local(&var, old, 4);
> >                         if (likely(ret == old))
> >                                 break;
> >                         old = ret;
> >                 } while (1);
> >
> 
> Great. Could you also put that into "patch-format"?
> 

Sure, can you point me to a git tree I should work on top of which
includes the per cpu infrastructure to extend ?

Mathieu


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Mathieu Desnoyers
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