From: Jens Axboe <axboe@kernel.dk>
To: Aaron Lu <aaron.lu@intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
Tejun Heo <tj@kernel.org>,
linux-pm@vger.kernel.org, linux-scsi@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org,
Aaron Lu <aaron.lwe@gmail.com>, Shane Huang <shane.huang@amd.com>,
Oliver Neukum <oneukum@suse.de>
Subject: Re: [PATCH v12 0/5] block layer runtime pm
Date: Fri, 22 Mar 2013 22:23:45 -0600 [thread overview]
Message-ID: <20130323042345.GR1628@kernel.dk> (raw)
In-Reply-To: <1364010148-8584-1-git-send-email-aaron.lu@intel.com>
On Sat, Mar 23 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 block/for-next:
> https://github.com/aaronlu/linux.git blockpm
>
> v12:
> - Split patch 1 into 2 patches, one introduces REQ_PM in block layer
> and one uses that flag in SCSI layer, suggested by Jens Axboe.
Thanks Aaron, I've applied 1, and 3-4. I'll leave 2 and 5 for James to
pickup. James, if you want me to carry them, just let me know.
--
Jens Axboe
next prev parent reply other threads:[~2013-03-23 4:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-23 3:42 [PATCH v12 0/5] block layer runtime pm Aaron Lu
2013-03-23 3:42 ` [PATCH v12 1/5] block: add a flag to identify PM request Aaron Lu
2013-03-23 3:42 ` [PATCH v12 2/5] scsi: use REQ_PM in sd's runtime suspend operation Aaron Lu
2013-03-23 3:42 ` [PATCH v12 3/5] block: add runtime pm helpers Aaron Lu
2013-03-23 3:42 ` [PATCH v12 4/5] block: implement runtime pm strategy Aaron Lu
2013-03-23 3:42 ` [PATCH v12 5/5] sd: change to auto suspend mode Aaron Lu
2013-03-23 4:23 ` Jens Axboe [this message]
2013-03-28 8:54 ` [PATCH v12 0/5] block layer runtime pm Aaron Lu
2013-10-10 1:40 ` block layer runtime pm and udisks Phillip Susi
2013-10-10 1:52 ` Aaron Lu
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