From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423185Ab3CWDgD (ORCPT ); Fri, 22 Mar 2013 23:36:03 -0400 Received: from mga03.intel.com ([143.182.124.21]:11493 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422664Ab3CWDgA (ORCPT ); Fri, 22 Mar 2013 23:36:00 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,896,1355126400"; d="scan'208";a="217977596" Message-ID: <514D2369.2010200@intel.com> Date: Sat, 23 Mar 2013 11:37:13 +0800 From: Aaron Lu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 MIME-Version: 1.0 To: Jens Axboe CC: Alan Stern , "Rafael J. Wysocki" , James Bottomley , Tejun Heo , linux-pm@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, Aaron Lu , Shane Huang , Oliver Neukum Subject: Re: [PATCH RESEND v11 0/4] block layer runtime pm References: <1363338305-4987-1-git-send-email-aaron.lu@intel.com> <20130322150958.GK25978@kernel.dk> In-Reply-To: <20130322150958.GK25978@kernel.dk> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/22/2013 11:09 PM, Jens Axboe wrote: > On Fri, Mar 15 2013, Aaron Lu wrote: >> In August 2010, Jens and Alan discussed about "Runtime PM and the block >> layer". http://marc.info/?t=128259108400001&r=1&w=2 >> And then Alan has given a detailed implementation guide: >> http://marc.info/?l=linux-scsi&m=133727953625963&w=2 >> >> To test: >> # ls -l /sys/block/sda >> /sys/devices/pci0000:00/0000:00:1f.2/ata1/host0/target0:0:0/0:0:0:0/block/sda >> >> # echo 10000 > /sys/devices/pci0000:00/0000:00:1f.2/ata1/host0/target0:0:0/0:0:0:0/power/autosuspend_delay_ms >> # echo auto > /sys/devices/pci0000:00/0000:00:1f.2/ata1/host0/target0:0:0/0:0:0:0/power/control >> Then you'll see sda is suspended after 10secs idle. >> >> [ 1767.680192] sd 2:0:0:0: [sda] Synchronizing SCSI cache >> [ 1767.680317] sd 2:0:0:0: [sda] Stopping disk >> >> And if you do some IO, it will resume immediately. >> [ 1791.052438] sd 2:0:0:0: [sda] Starting disk >> >> For test, I often set the autosuspend time to 1 second. If you are using >> a GUI, the 10 seconds delay may be too long that the disk can not enter >> runtime suspended state. >> >> Note that sd's runtime suspend callback will dump some kernel messages >> and the syslog daemon will write kernel message to /var/log/messages, >> making the disk instantly resume after suspended. So for test, the >> syslog daemon should better be temporarily stopped. >> >> A git repo for it, on top of v3.9-rc1: >> https://github.com/aaronlu/linux.git blockpm > > I think it's about time we get this in, but the patchset isn't very > friendly from a scsi vs block perspective. Can you re-shuffle the REQ_PM > change, just do a separate patch for that. I'll get it queued up for > 3.10 then. Thanks Jens. I'll spilt the first patch into two patches: one to introduce the REQ_PM flag in block layer and one to use that flag in SCSI layer. Will send out v12 soon. Best regards, Aaron