From: Aaron Lu <aaron.lu@intel.com>
To: "dbasehore ." <dbasehore@chromium.org>
Cc: Alan Stern <stern@rowland.harvard.edu>,
James Bottomley <JBottomley@parallels.com>,
Jeff Garzik <jgarzik@pobox.com>,
linux-ide@vger.kernel.org,
linux-kernel <linux-kernel@vger.kernel.org>,
SCSI development list <linux-scsi@vger.kernel.org>,
Linux-pm mailing list <linux-pm@vger.kernel.org>
Subject: Re: [PATCH 1/2] don't wait on disk to start on resume
Date: Mon, 04 Feb 2013 22:27:44 +0800 [thread overview]
Message-ID: <510FC560.6020002@intel.com> (raw)
In-Reply-To: <CAGAzgsqMhO9nppbooY5E2H5MXZ6VcCXR-P8S=nD7_7QJYrtmdw@mail.gmail.com>
On 02/04/2013 08:07 AM, dbasehore . wrote:
> On the topic that we do a fast return for both scsi and ata. Now I
> don't remember everything about this (and correct me if I'm wrong)
> since I figured this out a few months ago.
>
> There are some dependencies that scsi has on the resume path of ata. I
> think it's that before we can send the command to spin up the disk, we
> need to wait for the ata host controller to come up. As Aaron Lu
> pointed out, it takes seconds for the ata port to resume. On the hand,
I just did some more recording, the result is:
host controller takes 1ms or less to resume;
port reset takes the most time, almost the same as the whole port resume
callback, 2-4 seconds;
sd resume callback takes 16ms.
So for ata disks, the most time consuming part is in port's reset
routine, which is executed in port's resume callback.
-Aaron
next prev parent reply other threads:[~2013-02-04 14:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-21 4:35 [PATCH 1/2] don't wait on disk to start on resume Derek Basehore
2012-12-21 4:35 ` [PATCH 2/2] ata: don't wait " Derek Basehore
2012-12-22 14:32 ` [PATCH 1/2] don't wait on disk to start " Sergei Shtylyov
2013-01-31 22:00 ` dbasehore .
2013-01-31 22:27 ` James Bottomley
2013-01-31 22:32 ` dbasehore .
2012-12-23 11:49 ` James Bottomley
2013-01-31 22:02 ` dbasehore .
2013-01-31 22:26 ` James Bottomley
2013-02-01 11:51 ` Aaron Lu
2013-02-01 15:28 ` Alan Stern
2013-02-02 10:45 ` Aaron Lu
2013-02-02 15:09 ` Alan Stern
2013-02-03 6:23 ` Aaron Lu
2013-02-04 0:07 ` dbasehore .
2013-02-04 14:27 ` Aaron Lu [this message]
2013-02-04 8:04 ` Aaron Lu
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