Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751482AbXFWC7T (ORCPT ); Fri, 22 Jun 2007 22:59:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750948AbXFWC7K (ORCPT ); Fri, 22 Jun 2007 22:59:10 -0400 Received: from viefep18-int.chello.at ([213.46.255.22]:8340 "EHLO viefep34-int.chello.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750936AbXFWC7J (ORCPT ); Fri, 22 Jun 2007 22:59:09 -0400 Date: Sat, 23 Jun 2007 04:59:06 +0200 From: Carlo Wood To: Henrique de Moraes Holschuh Cc: Arjan van de Ven , Jeff Garzik , linux-kernel@vger.kernel.org Subject: Re: SATA Harddisk speed drop of 100 MB/s Message-ID: <20070623025906.GA24336@alinoe.com> Mail-Followup-To: Carlo Wood , Henrique de Moraes Holschuh , Arjan van de Ven , Jeff Garzik , linux-kernel@vger.kernel.org References: <20070620224847.GA5488@alinoe.com> <4679B2DE.9090903@garzik.org> <1182397012.2863.0.camel@laptopd505.fenrus.org> <20070622162142.GA603@alinoe.com> <20070622211746.GB21769@khazad-dum.debian.net> <20070622212758.GA6970@alinoe.com> <20070623013132.GA1702@khazad-dum.debian.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070623013132.GA1702@khazad-dum.debian.net> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1548 Lines: 39 On Fri, Jun 22, 2007 at 10:31:32PM -0300, Henrique de Moraes Holschuh wrote: > for i in /sys/block/sd*/queue/scheduler ; do echo -n "scheduler for $i was:" ; cat $i ; echo anticipatory > $i ; done > > Should show you the scheduler for all libata/scsi discs, and switch to > anticipatory. It probably works for hd* as well, but I don't have any > around to test. > > I had ridiculous md raid performance (on resync) using cfq at least once. > Unfortunately I never bothered trying to track it down, and I didn't check > the throughput after the resync was done either. Also, I don't recall the > kernel version, but it was either 2.6.18 or 2.6.20. Just one kernel version? The problem here is in every kernel revision after 551c012d7eea3dc5ec063c7ff9c718d39e77634f 2.6.20-rc2,rc3,rc4,rc5,rc6,rc7 ... 2.6.20 ... 2.6.21 ... 2.6.22-rc5 noop: Timing buffered disk reads: 254 MB in 3.00 seconds = 84.66 MB/sec anticipatory: Timing buffered disk reads: 252 MB in 3.02 seconds = 83.43 MB/sec deadline: Timing buffered disk reads: 258 MB in 3.02 seconds = 85.41 MB/sec cfq: Timing buffered disk reads: 194 MB in 3.03 seconds = 64.06 MB/sec The normal value is cfq. So, all other schedulars are somewhat faster, but still far from the correct 165 MB/s. -- Carlo Wood - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/