From: Andi Kleen <ak@suse.de>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] [RFC] Optimize select/poll by putting small data sets on the stack
Date: Wed, 4 Jan 2006 00:13:44 +0100 [thread overview]
Message-ID: <200601040013.44249.ak@suse.de> (raw)
In-Reply-To: <43BB03A7.3090604@cosmosbay.com>
On Wednesday 04 January 2006 00:07, Eric Dumazet wrote:
> Eric Dumazet a écrit :
> > Andi Kleen a écrit :
> >> This is a RFC for now. I would be interested in testing
> >> feedback. Patch is for 2.6.15.
> >>
> >> Optimize select and poll by a using stack space for small fd sets
> >>
> >> This brings back an old optimization from Linux 2.0. Using
> >> the stack is faster than kmalloc. On a Intel P4 system
> >> it speeds up a select of a single pty fd by about 13%
> >> (~4000 cycles -> ~3500)
> >
> > Was this result on UP or SMP kernel ? Preempt or not ?
> >
> > I think we might play in do_pollfd() and use fget_light()/fput_light()
> > instead of fget()/fput() that are somewhat expensive because of atomic
> > inc/dec on SMP.
>
> Just for completeness I include this patch against 2.6.15
Looks like a good idea.
-Andi
next prev parent reply other threads:[~2006-01-03 23:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-03 20:58 [PATCH] [RFC] Optimize select/poll by putting small data sets on the stack Andi Kleen
2006-01-03 22:14 ` Eric Dumazet
2006-01-03 23:05 ` Andi Kleen
2006-01-03 23:07 ` Eric Dumazet
2006-01-03 23:13 ` Andi Kleen [this message]
2006-01-03 22:22 ` Jesper Juhl
2006-01-03 23:07 ` Andi Kleen
2006-01-04 0:28 ` Arnd Bergmann
2006-01-04 0:33 ` Andi Kleen
2006-01-04 0:43 ` Eric Dumazet
2006-01-04 0:48 ` Andi Kleen
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