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From: Joe Perches <joe@perches.com>
To: Christoph Lameter <cl@gentwo.org>
Cc: starlight@binnacle.cx, 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: Tue, 04 Oct 2011 12:38:38 -0700	[thread overview]
Message-ID: <1317757118.3580.24.camel@Joe-Laptop> (raw)
In-Reply-To: <alpine.DEB.2.00.1110041358500.12199@router.home>

On Tue, 2011-10-04 at 14:16 -0500, Christoph Lameter wrote:
> On Mon, 3 Oct 2011, starlight@binnacle.cx wrote:
> > I've come to the conclusion that Eric is right
> > and the primary issue is an increase in the
> > cost of scheduler context switches.  Have
> > been watching this number and it has held
> > pretty close to 200k/sec under all scenarios
> > and kernel versions, so it has to be
> > a longer code-path, bigger cache pressure
> > or both in the scheduler.  Sadly this makes
> > newer kernels a no-go for us.
> We had similar experiences. Basically latency constantly gets screwed up
> by the new fancy features being added to the scheduler and network
> subsystem (most notorious is the new "fair" scheduler, 2.6.23 made a big
> step down).

Idly curious, have you compared bfs performance?
http://ck.kolivas.org/patches/bfs/bfs-faq.txt



  reply	other threads:[~2011-10-04 19:38 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-03 15:25 big picture UDP/IP performance question re 2.6.18 -> 2.6.32 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 [this message]
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
  -- 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  6:58 starlight
2011-10-05  8:53 ` Eric Dumazet
     [not found]   ` <1317804832.2473.25.camel@edumazet-HP-Compaq-6005-Pr o-SFF-PC>
2011-10-05 11:50     ` 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
2011-10-02  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
2011-10-01  5:30 starlight
2011-10-01  6:44 ` Eric Dumazet
2011-10-01 15:56   ` starlight

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