From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Thonke Subject: Re: Playing with SATA NCQ Date: Sun, 29 May 2005 22:12:40 +0200 Message-ID: <429A2238.8010604@gmail.com> References: <20050526140058.GR1419@suse.de> <429793C8.8090007@gmail.com> <42979C4F.8020007@pobox.com> <42979FA3.1010106@gmail.com> <20050528121258.GA17869@suse.de> <4299BD23.6010004@gmail.com> <20050529190259.GA29770@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from wproxy.gmail.com ([64.233.184.195]:42577 "EHLO wproxy.gmail.com") by vger.kernel.org with ESMTP id S261426AbVE2UMq (ORCPT ); Sun, 29 May 2005 16:12:46 -0400 Received: by wproxy.gmail.com with SMTP id 69so2134531wri for ; Sun, 29 May 2005 13:12:46 -0700 (PDT) In-Reply-To: <20050529190259.GA29770@suse.de> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jens Axboe Cc: Jeff Garzik , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Jens Axboe schrieb: >On Sun, May 29 2005, Michael Thonke wrote: > > >>Jens Axboe wrote, >> >> >> >>>There's really nothing to be tuned. If NCQ is enabled for your drive, it >>>will be printed in dmesg after the lba48 flag, such as: >>> >>>ata1: dev 0 ATA, max UDMA/133, 488281250 sectors lba48 ncq >>> >>>If you don't see NCQ there, your drive/controller doesn't support it. >>>Likewise you will have a queueing depth of > 1 if NCQ is enabled, check >>>/sys/block/sdX/device/queue_depth to see what the configured queueing >>>depth is for that device. >>> >>> >>> >>> >>> >>Hi Jens, >> >>thanks for the short info now my next question how many queue depths >>are healty and wanted? >> >>For my Intel Corporation 82801GR/GH (ICH7 Family) Serial ATA Storage >>Controllers cc=AHCI (rev 01) >>and Samsung Hd160JJ SATAII drive the default queue is 30 >> >> ioGL64NX_MACH~# cat /sys/block/sda/device/{model,queue_depth} >> SAMSUNG HD160JJ >> 30 >> >> hdparm -Tt /dev/sda >> >> /dev/sda: >> Timing cached reads: 4724 MB in 2.00 seconds = 2360.00 MB/sec >> Timing buffered disk reads: 164 MB in 3.02 seconds = 54.28 MB/sec >> >>On random access the drives is a bit noisy but the subjective feeling >>is great everything goes a bit faster. >> >> > >You should see a nice performance improvement on random reads mainly, >with streamed threaded reads being a bit faster as well. Write >performance will be the same, if you had write back caching on before. >So the real win is random reads, and that can be a pretty big win. > >Actually I would say that the drive should sound _less_ noisy if NCQ is >being really effective. Hard to judge of course, very subjective :) > > > Well the subjective feeling is great through! What I noticed is a improvement on rsync (goes slighty faster drive to drive). The noise decrease now it only make noise on very heavy IO reads and writes. >>And whats about the option /sys/block/sdx/device/queue_type = simple >>what can be done here? >> >> > >Nothing, unfortunately NCQ doesn't provided any way of doing ordered >tags. The only tunable is the queue_depth, you can set that anywhere >between 1 and 30. > > > So way my drive got default 30 as queue_depth on AHCI as you mentoined in the next mail 2-4 should be suitable and enough/normal? Thanks for the informations Greets Michael