From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lu Subject: Re: [PATCH RESEND v11 0/4] block layer runtime pm Date: Sat, 23 Mar 2013 11:37:13 +0800 Message-ID: <514D2369.2010200@intel.com> References: <1363338305-4987-1-git-send-email-aaron.lu@intel.com> <20130322150958.GK25978@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130322150958.GK25978@kernel.dk> Sender: linux-ide-owner@vger.kernel.org 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 List-Id: linux-pm@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