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From: starlight@binnacle.cx
To: Joe Perches <joe@perches.com>, Christoph Lameter <cl@gentwo.org>,
	Serge Belyshev <belyshev@depni.sinp.msu.ru>,
	Con Kolivas <kernel@kolivas.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	linux-kernel@vger.kernel.org, netdev <netdev@vger.kernel.org>,
	Willy Tarreau <w@1wt.eu>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Stephen Hemminger <stephen.hemminger@vyatta.com>
Subject: Re: big picture UDP/IP performance question re 2.6.18 -> 2.6.32
Date: Wed, 05 Oct 2011 02:58:17 -0400	[thread overview]
Message-ID: <6.2.5.6.2.20111005025227.03a9d9f0@binnacle.cx> (raw)

Final note:

I had captured latency measurements for
two of the three kernels.  Just ran
2.6.18(rhel5) and the results are
stunning.  The older kernel is much,
much better then the newer kernel.

Average latency is three times better
and the standard deviation is six
time better.  As in 300% and 600%.

Latency here is the time it takes
a packet to travel from the kernel
(where it is timestamped) till it
reaches the final consumption point
in the application.

Makes me think that the old kernel
is better at keeping caches hot and
scheduling woken threads on the same
cores as the threads that triggered
them.

             reply	other threads:[~2011-10-05  6:58 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-05  6:58 starlight [this message]
2011-10-05  8:53 ` big picture UDP/IP performance question re 2.6.18 -> 2.6.32 Eric Dumazet
     [not found]   ` <1317804832.2473.25.camel@edumazet-HP-Compaq-6005-Pr o-SFF-PC>
2011-10-05 11:50     ` starlight
  -- strict thread matches above, loose matches on Subject: below --
2011-10-07  3:27 starlight
2011-10-07  5:40 ` Eric Dumazet
2011-10-07  6:13   ` starlight
2011-10-07 18:09     ` chetan loke
     [not found]       ` <CAAsGZS4s1wTWW1j7FRUWW9jqpPUVF3Q46AMa7+njvE1ckX0Snw @mail.gmail.com>
2011-10-07 18:37         ` starlight
2011-10-07 19:27           ` chetan loke
     [not found]             ` <CAAsGZS4b2F9N3nV3TNu5xG+=2d0L0ncste4xv2vqoVFb1pOxEw @mail.gmail.com>
2011-10-07 19:41               ` starlight
2011-10-07 20:07           ` Ben Hutchings
2011-10-11 16:24   ` Chris Friesen
2011-10-07  2:33 starlight
2011-10-07  2:24 starlight
2011-10-05  6:11 starlight
2011-10-05  3:35 starlight
2011-10-03 18:02 starlight
2011-10-05  6:53 ` Eric Dumazet
2011-10-03 15:25 starlight
2011-10-03 16:16 ` Eric Dumazet
     [not found]   ` <1317658588.2442.5.camel@edumazet-HP-Compaq-6005-Pro -SFF-PC>
2011-10-03 16:28     ` starlight
2011-10-04 19:16 ` Christoph Lameter
2011-10-04 19:38   ` Joe Perches
2011-10-04 19:42     ` Christoph Lameter
2011-10-04 19:49       ` Serge Belyshev
2011-10-04 20:03         ` Christoph Lameter
2011-10-04 20:12           ` Serge Belyshev
2011-10-04 22:32             ` Con Kolivas
2011-10-04 19:45     ` starlight
2011-10-05 13:22   ` Peter Zijlstra
2011-10-05 14:26     ` Christoph Lameter
2011-10-05 15:12       ` Andi Kleen
2011-10-05 15:33       ` Peter Zijlstra
2011-10-05 15:12     ` starlight
2011-10-02  5:33 starlight
2011-10-02  7:21 ` Eric Dumazet
2011-10-02  8:03   ` Eric Dumazet
2011-10-02 14:47   ` Stephen Hemminger
2011-10-02 15:06   ` starlight
2011-10-04 19:54     ` Loke, Chetan
2011-10-01 21:13 starlight
2011-10-01 18:16 starlight
2011-10-01 18:40 ` Willy Tarreau
2011-10-01 19:11 ` Eric Dumazet
2011-10-01 19:43   ` starlight
     [not found] <6.2.5.6.2.20111001012019.05c05b80@flumedata.com>
2011-10-01  6:44 ` Eric Dumazet
2011-10-01 15:56   ` starlight

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