From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753420AbXFWHDv (ORCPT ); Sat, 23 Jun 2007 03:03:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751628AbXFWHDm (ORCPT ); Sat, 23 Jun 2007 03:03:42 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:36236 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751584AbXFWHDl (ORCPT ); Sat, 23 Jun 2007 03:03:41 -0400 Message-ID: <467CC5C5.6040201@garzik.org> Date: Sat, 23 Jun 2007 03:03:33 -0400 From: Jeff Garzik User-Agent: Thunderbird 1.5.0.12 (X11/20070530) MIME-Version: 1.0 To: Carlo Wood CC: Tejun Heo , Manoj Kasichainula , linux-kernel@vger.kernel.org, IDE/ATA development list Subject: Re: SATA RAID5 speed drop of 100 MB/s References: <20070620224847.GA5488@alinoe.com> <4679B2DE.9090903@garzik.org> <20070622214859.GC6970@alinoe.com> In-Reply-To: <20070622214859.GC6970@alinoe.com> Content-Type: multipart/mixed; boundary="------------030600080503070105010006" X-Spam-Score: -4.3 (----) X-Spam-Report: SpamAssassin version 3.1.9 on srv5.dvmed.net summary: Content analysis details: (-4.3 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------030600080503070105010006 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Carlo Wood wrote: > The dmesg output of 33480a0ede8dcc7e6483054279008f972bd56fd3 (thus > "before") is: [...] > And the dmesg output of 551c012d7eea3dc5ec063c7ff9c718d39e77634f (thus > "after") is: [...] Your disk configurations are quite radically different between the two kernels (see attached diff for key highlights). The new behavior of the more recent kernel (551c012d7...) is that it now fully drives your hardware :) The reset problems go away, NCQ is enabled, and if you had 3.0Gbps drives (you don't) they would be driven at a faster speed. Given that some drives might be better tuned for benchmarks in non-queued mode, and that a major behavior difference is that your drives are now NCQ-enabled, the first thing I would suggest you try is disabling NCQ: http://linux-ata.org/faq.html#ncq Other indicators are the other changes in the "ahci 0000:00:1f.2: flags:" line, which do affect other behaviors, though none so important to RAID5 performance as NCQ, I would think. Turning on NCQ also potentially affects barrier behavior in RAID, though I'm guessing that is not a factor here. Jeff --------------030600080503070105010006 Content-Type: text/plain; name="diff.txt" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="diff.txt" -ahci 0000:00:1f.2: AHCI 0001.0100 32 slots 6 ports ? Gbps 0x3f impl SATA mode -ahci 0000:00:1f.2: flags: 64bit ilck stag led pmp pio +ahci 0000:00:1f.2: AHCI 0001.0100 32 slots 6 ports 3 Gbps 0x3f impl SATA mode +ahci 0000:00:1f.2: flags: 64bit ncq ilck stag pm led clo pmp pio slum part scsi0 : ahci -ata1: softreset failed (port busy but CLO unavailable) -ata1: softreset failed, retrying in 5 secs ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300) -ata1.00: ATA-7, max UDMA/133, 145226112 sectors: LBA48 NCQ (depth 0/32) +ata1.00: ATA-7, max UDMA/133, 145226112 sectors: LBA48 NCQ (depth 31/32) ata1.00: ata1: dev 0 multi count 0 ata1.00: configured for UDMA/133 scsi1 : ahci -ata2: softreset failed (port busy but CLO unavailable) -ata2: softreset failed, retrying in 5 secs ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 300) -ata2.00: ATA-7, max UDMA/133, 145226112 sectors: LBA48 NCQ (depth 0/32) +ata2.00: ATA-7, max UDMA/133, 145226112 sectors: LBA48 NCQ (depth 31/32) ata2.00: ata2: dev 0 multi count 0 ata2.00: configured for UDMA/133 scsi2 : ahci ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 300) -ata3.00: ATA-7, max UDMA/133, 145226112 sectors: LBA48 NCQ (depth 0/32) +ata3.00: ATA-7, max UDMA/133, 145226112 sectors: LBA48 NCQ (depth 31/32) ata3.00: ata3: dev 0 multi count 0 ata3.00: configured for UDMA/133 scsi3 : ahci ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 300) -ata4.00: ATA-7, max UDMA/133, 625142448 sectors: LBA48 NCQ (depth 0/32) +ata4.00: ATA-7, max UDMA/133, 625142448 sectors: LBA48 NCQ (depth 31/32) ata4.00: configured for UDMA/133 scsi4 : ahci ata5: SATA link up 1.5 Gbps (SStatus 113 SControl 300) --------------030600080503070105010006--