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From: Alan Stern <stern@rowland.harvard.edu>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Phillip Susi <psusi@ubuntu.com>,
	Todd E Brandt <todd.e.brandt@linux.intel.com>,
	Aaron Lu <aaron.lu@intel.com>, Tejun Heo <tj@kernel.org>,
	SCSI development list <linux-scsi@vger.kernel.org>
Subject: Re: Disk spin-up optimization during system resume
Date: Tue, 21 Jan 2014 10:44:37 -0500 (EST)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.1401211042250.1272-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <CAPcyv4iZ4Qfzd2tZUOSbz9bGUqfzOD3zamFw6gip4ceB3=SK+Q@mail.gmail.com>

On Tue, 21 Jan 2014, Dan Williams wrote:

> On Sat, Jan 18, 2014 at 6:08 AM, Alan Stern <stern@rowland.harvard.edu> wrote:
> > On Fri, 17 Jan 2014, Dan Williams wrote:
> >
> >> I think it's a bit of an interface surprise to have pm_runtime disable
> >> have side effects only for scsi_disk devices.  I think lazy_resume
> >> needs to be an explicit attribute of the disk.  For ata devices any
> >> command wakes up the drive.  Perhaps we could simply do the same for
> >> scsi devices.  In lazy_resume mode flag the device as "needs spinup"
> >> at sd_resume time and schedule it when a command arrives.
> >
> > What you have just described is essentially what runtime PM does.
> 
> Deliberately so...
> 
> > There's no need to implement it any other way.  And this explains why
> > disabling runtime PM would also disable lazy resume.
> 
> The need is to avoid tying rpm and dpm ops together in surprising new
> ways that require userspace to change if it wants to keep the default
> behavior of hiding resume latency as much as possible.  A lazy_resume
> knob vs changing the default let's the few setups that care set the
> power-up in standby mode.

That's why I proposed it.  What are you getting at?

>  It should also "perform" better given it
> does not require the disk to be runtime suspended prior to system
> suspend, it will unconditionally resume on demand.

None of my posts in this email thread have required the disk to be in 
runtime suspend prior to the system suspend.

Alan Stern


  parent reply	other threads:[~2014-01-21 15:44 UTC|newest]

Thread overview: 165+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-17 19:33 [PATCH/RESEND v2 0/2] SATA disk resume time optimization Todd E Brandt
2013-11-07  1:53 ` Phillip Susi
2013-11-07  1:57   ` [PATCH 1/3] sd: don't bother spinning up disks on resume Phillip Susi
2013-11-07 18:21     ` Douglas Gilbert
2013-11-07 21:16       ` Phillip Susi
2013-11-16 18:20         ` James Bottomley
2013-11-17  3:50           ` Phillip Susi
2013-11-17  6:43             ` James Bottomley
2013-11-17 16:15               ` Phillip Susi
2013-11-17 23:54                 ` Douglas Gilbert
2013-11-18  1:06                   ` Phillip Susi
2013-11-18 15:54                     ` Phillip Susi
2013-11-20 14:23                       ` Mark Lord
2013-11-20 14:48                         ` Phillip Susi
2013-11-28  1:39                           ` Phillip Susi
2013-11-18  0:09                 ` James Bottomley
2013-11-18  1:11                   ` Phillip Susi
2013-11-16  5:23       ` Mark Lord
2013-11-16 14:52         ` Phillip Susi
2013-11-07  1:57   ` [PATCH 2/3] libata: resume in the background Phillip Susi
2013-11-07  1:57   ` [PATCH 3/3] libata: don't start disks on resume Phillip Susi
2013-11-09  1:20   ` [PATCH/RESEND v2 0/2] SATA disk resume time optimization Todd E Brandt
2013-11-09 20:59     ` Phillip Susi
2013-11-09 21:03       ` [PATCH 0/6] Let sleeping disks lie Phillip Susi
2013-12-16 23:30         ` Phillip Susi
2013-12-16 23:30           ` [PATCH 1/6] libata: use sleep instead of standby command Phillip Susi
2013-12-16 23:30           ` [PATCH 2/6] libata: avoid waking disk for several commands Phillip Susi
2013-12-16 23:30           ` [PATCH 3/6] libata: resume in the background Phillip Susi
2014-01-10 22:26             ` Dan Williams
2014-01-11  2:25               ` Phillip Susi
2014-01-11  3:11                 ` Dan Williams
2013-12-16 23:30           ` [PATCH 4/6] libata: don't start disks on resume Phillip Susi
2013-12-16 23:30           ` [PATCH 5/6] sd: don't start disks on system resume Phillip Susi
2013-12-17  6:43             ` James Bottomley
2013-12-17 15:01               ` Phillip Susi
2013-12-17 17:48                 ` James Bottomley
2013-12-17 18:30                   ` Phillip Susi
2013-12-16 23:30           ` [PATCH 6/6] libata: return power status in REQUEST SENSE command Phillip Susi
2013-12-17 18:02             ` Sergei Shtylyov
2013-12-17 18:35               ` Phillip Susi
2014-01-06  2:14           ` REQ_PM vs REQ_TYPE_PM_RESUME Phillip Susi
2014-01-06  7:36             ` Sujit Reddy Thumma
2014-01-06  9:15               ` Aaron Lu
2014-01-06 14:40                 ` Phillip Susi
2014-01-06 15:38                   ` Alan Stern
2014-01-07  2:44                     ` Phillip Susi
2014-01-07 15:20                       ` Alan Stern
2014-01-07 15:40                         ` Phillip Susi
2014-01-07 15:56                           ` Alan Stern
2014-01-09 18:29                           ` Douglas Gilbert
2014-01-09 19:20                             ` Phillip Susi
2014-01-10  5:23                               ` Douglas Gilbert
2014-01-10 14:29                                 ` Phillip Susi
2014-01-07  7:49                   ` Aaron Lu
2014-01-07 14:50                     ` Phillip Susi
2014-01-08  1:03                       ` Aaron Lu
2014-01-08  1:16                         ` Phillip Susi
2014-01-08  1:32                           ` Aaron Lu
2014-01-08  1:53                             ` Phillip Susi
2014-01-08  2:11                               ` Aaron Lu
2014-01-08  2:19                                 ` Phillip Susi
2014-01-08  2:36                                   ` Aaron Lu
2014-01-08  5:24                                     ` Phillip Susi
2014-01-08  7:00                                       ` Aaron Lu
2014-01-08 19:30                                         ` Phillip Susi
2014-01-07 15:25                     ` Alan Stern
2014-01-07 15:43                       ` Phillip Susi
2014-01-07 16:08                         ` Alan Stern
2014-01-07 16:37                           ` Phillip Susi
2014-01-07 18:05                             ` Alan Stern
2014-01-07 18:43                               ` Phillip Susi
2014-01-07 19:18                                 ` Alan Stern
2014-01-07 23:47                                   ` Phillip Susi
2014-01-08 17:46                                     ` Alan Stern
2014-01-08 18:31                                       ` Alan Stern
2014-01-08 20:44                                         ` Allow runtime suspend during system resume Alan Stern
2014-01-08 21:17                                           ` Phillip Susi
2014-01-08 21:34                                             ` Alan Stern
2014-01-09 10:14                                               ` Ulf Hansson
2014-01-09 15:41                                                 ` Alan Stern
2014-01-08 22:55                                           ` Rafael J. Wysocki
2014-01-08 23:24                                             ` Alan Stern
2014-01-09  0:05                                               ` Rafael J. Wysocki
2014-01-09 15:32                                                 ` Alan Stern
2014-01-09 15:50                                                   ` Phillip Susi
2014-01-09 16:08                                                     ` Alan Stern
2014-01-09 16:30                                                       ` Phillip Susi
2014-01-09 17:04                                                         ` Alan Stern
2014-01-10  1:25                                                   ` Rafael J. Wysocki
2014-01-10  1:55                                                     ` Phillip Susi
2014-01-10 13:35                                                       ` Rafael J. Wysocki
2014-01-10 14:46                                                         ` Phillip Susi
2014-01-10 15:25                                                     ` Alan Stern
2014-01-10 23:02                                                       ` Rafael J. Wysocki
2014-01-11  2:08                                                         ` Phillip Susi
2014-01-11 22:50                                                           ` Alan Stern
2014-01-12  1:50                                                             ` Phillip Susi
2014-01-11 22:34                                                         ` Alan Stern
2014-01-08 20:20                                       ` REQ_PM vs REQ_TYPE_PM_RESUME Phillip Susi
2014-01-08 21:21                                         ` Alan Stern
2014-01-08 21:50                                           ` Phillip Susi
2014-01-09  1:29                                           ` Aaron Lu
2014-01-09 12:17                                             ` Rafael J. Wysocki
2014-01-09 13:18                                               ` Rafael J. Wysocki
2014-01-09 15:40                                             ` Alan Stern
2014-01-09 15:53                                               ` Phillip Susi
2014-01-09 16:14                                                 ` Alan Stern
2014-01-09 16:34                                                   ` Phillip Susi
2014-01-09 17:06                                                     ` Alan Stern
2014-01-16 16:59                                                 ` Disk spin-up optimization during system resume Alan Stern
2014-01-16 18:04                                                   ` Todd E Brandt
2014-01-16 18:33                                                     ` Phillip Susi
2014-01-16 20:05                                                     ` Alan Stern
2014-01-16 22:04                                                       ` Todd E Brandt
2014-01-17 14:57                                                         ` Alan Stern
2014-01-17 19:31                                                           ` Dan Williams
2014-01-17 20:15                                                             ` Alan Stern
2014-01-17 20:24                                                               ` Tejun Heo
2014-01-17 20:55                                                                 ` Phillip Susi
2014-01-18 14:04                                                                   ` Tejun Heo
2014-01-18  1:36                                                                 ` Todd E Brandt
2014-01-18  1:41                                                                 ` Alan Stern
2014-01-18  2:15                                                                   ` Dan Williams
2014-01-18  2:33                                                                     ` Alan Stern
2014-01-18  3:24                                                                   ` Phillip Susi
2014-01-18 13:59                                                                   ` Tejun Heo
2014-01-17 20:49                                                             ` Phillip Susi
2014-01-17 22:17                                                               ` Dan Williams
2014-01-18  3:18                                                                 ` Phillip Susi
2014-01-18  4:09                                                                   ` Dan Williams
2014-01-18 14:08                                                                     ` Alan Stern
2014-01-21 10:12                                                                       ` Dan Williams
2014-01-21 14:37                                                                         ` Phillip Susi
2014-01-21 16:03                                                                           ` Alan Stern
2014-01-21 16:18                                                                             ` Phillip Susi
2014-01-21 16:49                                                                               ` Alan Stern
2014-01-21 15:44                                                                         ` Alan Stern [this message]
2014-01-21 16:18                                                                           ` Dan Williams
2014-01-21 16:55                                                                             ` Dan Williams
2014-01-20 12:38                                                                     ` CrashPlan Pro
2014-01-20 14:30                                                                       ` Phillip Susi
2014-01-18  1:24                                                           ` Todd E Brandt
2014-01-18  3:20                                                             ` Phillip Susi
2014-01-16 18:39                                                   ` Phillip Susi
2014-01-16 20:08                                                     ` Alan Stern
2014-01-17 10:16                                                   ` Oliver Neukum
2014-01-17 10:21                                                     ` Tejun Heo
2014-01-17 18:18                                                       ` Alan Stern
2014-01-17 18:39                                                       ` James Bottomley
2014-01-17 19:07                                                         ` Tejun Heo
2013-11-09 21:03       ` [PATCH 1/6] libata: use sleep instead of standby command Phillip Susi
2013-11-09 21:03       ` [PATCH 2/6] libata: avoid waking disk to check power Phillip Susi
2013-11-11 13:05         ` Sergei Shtylyov
2013-11-09 21:03       ` [PATCH 3/6] sd: don't bother spinning up disks on resume Phillip Susi
2013-11-11 13:08         ` Sergei Shtylyov
2013-11-11 14:28           ` Phillip Susi
2013-11-09 21:03       ` [PATCH 4/6] libata: resume in the background Phillip Susi
2013-11-11 13:10         ` Sergei Shtylyov
2013-11-09 21:03       ` [PATCH 5/6] libata: don't start disks on resume Phillip Susi
2013-11-09 21:03       ` [PATCH 6/6] libata: fake some more commands when drive is sleeping Phillip Susi
2013-11-11 16:59       ` [PATCH/RESEND v2 0/2] SATA disk resume time optimization Todd E Brandt
2013-11-11 17:08         ` Phillip Susi
2013-12-17 12:15           ` Tejun Heo
2013-12-17 14:24             ` Phillip Susi
2013-11-27 16:18 ` Phillip Susi

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