From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932127AbWFFHDJ (ORCPT ); Tue, 6 Jun 2006 03:03:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932126AbWFFHDJ (ORCPT ); Tue, 6 Jun 2006 03:03:09 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:52231 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S932127AbWFFHDH (ORCPT ); Tue, 6 Jun 2006 03:03:07 -0400 Date: Tue, 6 Jun 2006 09:05:39 +0200 From: Jens Axboe To: Tejun Heo Cc: Robert Hancock , Bill Davidsen , linux-kernel Subject: Re: [git patch] libata resume fix Message-ID: <20060606070539.GO4400@suse.de> References: <6hAdo-5CV-5@gated-at.bofh.it> <6hXD0-6Y9-1@gated-at.bofh.it> <6icsx-4vp-33@gated-at.bofh.it> <6ih8Y-3ba-15@gated-at.bofh.it> <6iH3h-2xw-59@gated-at.bofh.it> <447E5EAD.5070808@shaw.ca> <20060601134802.GK4400@suse.de> <4485269B.8060602@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4485269B.8060602@gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 06 2006, Tejun Heo wrote: > Hi, Jens. > > Jens Axboe wrote: > >On Wed, May 31 2006, Robert Hancock wrote: > >>Bill Davidsen wrote: > >>>The trade-off is that if I have a 15k rpm SCSI drive, it would take a > >>>lot of design changes to make it spin up quickly, and improve a function > >>>which is usually done on a server once every MTBF when replacing the > >>>failed unit. > >>> > >>>I think the majority of very large or very fast drives are in systems > >>>which don't (deliberately) power cycles often, in rooms where heat is an > >>>issue. And to spin up quickly take a larger power supply... 30 sec is > >>>fine with most users. > >>> > >>>Couldn't find a spin-up time for the new Seagate 750GB drive, but the > >>>seek sure is fast! > >>I wouldn't guess that even a 15K drive would take nearly that long. For > >>boot time on servers it doesn't matter much though, disk spinup time is > > > >I do use a 15K rpm drive in my workstation (hello git!), and the spin up > >really isn't that bad. Less than 10 seconds for the actual spin up, I > >would say. > > Can you measure spin up time for your 15k's? Some controllers can't > catch the first D2H FIS after POR and have to wait unconditionally for > spin up for hotplug & resuming from suspend. Currently 8 sec wait is > used but it seems insufficient for your drives. Failing to spinup in > that 8 secs would probably result in timeout of the first reset attempt > and retrial - which currently takes > 30 secs. > > Spin-up time can be measured by first issuing STANDBY and then time how > long IDLE IMMEDIATE takes, I think. The 15K RPM is a SCSI drive, I haven't seen any SATA 15K rpm drives yet. I have the same model in another box, I can measure spinup with START_STOP unit there. I will do so later today, when I fire it up, if you still want to know? -- Jens Axboe