From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: poor sata performance on 2.6 Date: Thu, 15 Apr 2004 21:05:34 -0400 Sender: linux-kernel-owner@vger.kernel.org Message-ID: <407F315E.2000809@pobox.com> References: <200404150236.05894.kos@supportwizard.com> <1082039593.19568.75.camel@lotte.street-vision.com> <200404151848.05857.kos@supportwizard.com> <200404152030.51052.vda@port.imtp.ilyichevsk.odessa.ua> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200404152030.51052.vda@port.imtp.ilyichevsk.odessa.ua> To: Denis Vlasenko Cc: Konstantin Sobolev , Justin Cormack , Ryan Geoffrey Bourgeois , Kernel mailing list , linux-ide@vger.kernel.org List-Id: linux-ide@vger.kernel.org Denis Vlasenko wrote: > On Thursday 15 April 2004 17:48, Konstantin Sobolev wrote: > >>On Thursday 15 April 2004 18:33, Justin Cormack wrote: >> >>>On Thu, 2004-04-15 at 15:26, Konstantin Sobolev wrote: >>> >>>>On Thursday 15 April 2004 18:00, Justin Cormack wrote: >>>> >>>>>hmm, odd. I get 50MB/s or so from normal (7200, 8MB cache) WD disks, >>>>>and Seagate from the same controller. Can you send lspci, >>>>>/proc/interrupts and dmesg... >>>> >>>>Attached are files for 2.6.5-mm5 with highmem, ACPI and APIC turned >>>>off. >>> >>>ah. Make a filesystem on it and mount it and try again. I see you have >>>no partition table and so probably no filesystem. This means the block >>>size is set to default 512byte not 4k which makes disk operations slow. >>>Any filesystem should default to block size of 4k, eg ext2. >> >>Very interesting! >>created partition table, >>kos sata # mkfs.ext2 /dev/sda1 >>[..skipped..] >>kos mnt # cd / >>kos / # mkdir wd >>kos / # mount /dev/sda1 /wd >>kos / # hdparm -t -a8192 /dev/sda >> >>/dev/sda: >> setting fs readahead to 8192 >> readahead = 8192 (on) >> Timing buffered disk reads: 82 MB in 3.03 seconds = 27.02 MB/sec >> >>kos / # mount | grep sda >>/dev/sda1 on /wd type ext2 (rw) >>kos / # hdparm -t -a8192 /dev/sda >> >>/dev/sda: >> setting fs readahead to 8192 >> readahead = 8192 (on) >> Timing buffered disk reads: 206 MB in 3.02 seconds = 68.15 MB/sec >>kos / # hdparm -t -a8192 /dev/sda >> >>/dev/sda: >> setting fs readahead to 8192 >> readahead = 8192 (on) >> Timing buffered disk reads: 206 MB in 3.02 seconds = 68.18 MB/sec >> >>So first time it gave the same loosy 27 MB/s and subsequent tests give >>pretty good 68 MB/s! Why? > > > Time to CC ide/libata/block layer folks > > Jeff Garzik > libata man It seems like the situation is already resolved, to me. When you mount a filesystem, it changes the default block size (512 or 1024) to the filesystem block size, normally 4096. This would certainly increase the throughput. Jeff