From: Jim Rees <rees@umich.edu>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Olga Kornievskaia <aglo@citi.umich.edu>,
Jeff Moyer <jmoyer@redhat.com>,
Jens Axboe <jens.axboe@oracle.com>,
linux-kernel@vger.kernel.org, "Rafael J. Wysocki" <rjw@sisk.pl>,
"J. Bruce Fields" <bfields@fieldses.org>,
linux-nfs@vger.kernel.org
Subject: Re: 2.6.30-rc deadline scheduler performance regression for iozone over NFS
Date: Wed, 13 May 2009 14:25:24 -0400 [thread overview]
Message-ID: <20090513182524.GA20778@merit.edu> (raw)
In-Reply-To: <20090513093229.097b47d2.akpm@linux-foundation.org>
Andrew Morton wrote:
Jeff's computer got slower. Can we fix that?
TCP autotuning can reduce performance by up to about 10% in some cases.
Jeff found one of these cases. While the autotuning penalty never exceeds
10% as far as I know, I can provide examples of other cases where autotuning
improves nfsd performance by more than a factor of 100.
The right thing is to fix autotuning. If autotuning is considered too
broken to use, it should be turned off everywhere, not just in nfsd, as it
hurts/benefits all TCP clients, not just nfs.
This topic has been discussed before on netdev:
http://www.spinics.net/lists/netdev/msg68650.html
http://www.spinics.net/lists/netdev/msg68155.html
next prev parent reply other threads:[~2009-05-13 18:34 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-23 14:01 2.6.30-rc deadline scheduler performance regression for iozone over NFS Jeff Moyer
2009-05-08 19:01 ` Andrew Morton
2009-05-11 8:14 ` Jens Axboe
2009-05-11 13:53 ` Jeff Moyer
2009-05-11 16:58 ` Jens Axboe
2009-05-13 3:29 ` Jeff Moyer
2009-05-13 3:44 ` Andrew Morton
2009-05-13 14:58 ` Jeff Moyer
2009-05-13 16:20 ` Olga Kornievskaia
2009-05-13 16:32 ` Andrew Morton
2009-05-13 18:16 ` Olga Kornievskaia
2009-05-13 19:06 ` Jeff Moyer
2009-05-13 18:25 ` Jim Rees [this message]
2009-05-13 19:45 ` Trond Myklebust
2009-05-13 19:29 ` Jeff Moyer
2009-05-13 23:45 ` Trond Myklebust
2009-05-14 13:34 ` Jeff Moyer
2009-05-14 14:33 ` Trond Myklebust
2009-05-14 14:38 ` Jeff Moyer
2009-05-14 15:00 ` Jeff Moyer
2009-05-17 19:10 ` Trond Myklebust
2009-05-17 19:12 ` Trond Myklebust
2009-05-18 14:15 ` Jeff Moyer
2009-05-22 23:45 ` J. Bruce Fields
2009-05-14 17:55 ` J. Bruce Fields
2009-05-14 18:26 ` Trond Myklebust
2009-05-15 21:37 ` J. Bruce Fields
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