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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: netdev@vger.kernel.org
Subject: Re: UDP regression with packets rates < 10k per sec
Date: Tue, 15 Sep 2009 07:29:34 +0200	[thread overview]
Message-ID: <4AAF263E.9010405@gmail.com> (raw)
In-Reply-To: <alpine.DEB.1.10.0909141708150.8051@V090114053VZO-1>

Christoph Lameter a écrit :
> Where are we on this? Definitely a regression?

??

I tried to reproduce your numbers and failed on my machines.

2.6.31 is actually faster than 2.6.22 on the bench you provided.

Must be specific to the hardware I guess ?


As text size presumably is bigger in 2.6.31, fetching code
in cpu caches to handle 10 packets per second is what we call
a cold path anyway.

If you want to make it a fast path, you want to make sure code its
always hot in cpu caches, and find a way to inject packets into
the kernel to make sure cpu keep the path hot.


  reply	other threads:[~2009-09-15  5:30 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-08 22:38 UDP regression with packets rates < 10k per sec Christoph Lameter
2009-09-08 22:52 ` Eric Dumazet
2009-09-09 14:01   ` Christoph Lameter
2009-09-09 15:09     ` Eric Dumazet
2009-09-09 16:47       ` Christoph Lameter
2009-09-09 17:06         ` Eric Dumazet
2009-09-09 17:55           ` Christoph Lameter
2009-09-10 20:37             ` Eric Dumazet
2009-09-10 21:36               ` Christoph Lameter
2009-09-10 21:37               ` Eric Dumazet
2009-09-10 21:42                 ` Christoph Lameter
2009-09-14 21:10                   ` Christoph Lameter
2009-09-15  5:29                     ` Eric Dumazet [this message]
2009-09-15 14:07                       ` Christoph Lameter
2009-09-15 17:26                         ` Eric Dumazet
2009-09-15 20:25                           ` Christoph Lameter
2009-09-15 19:02                             ` Eric Dumazet
2009-09-25 14:19                             ` Eric Dumazet
2009-09-26 16:13                               ` Christoph Lameter
2009-09-10 21:39               ` Christoph Lameter
2009-09-09 17:08         ` Eric Dumazet
2009-09-09 17:26           ` Christoph Lameter

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