Messages in this thread | | | Date | Mon, 04 Feb 2013 22:27:44 +0800 | From | Aaron Lu <> | Subject | Re: [PATCH 1/2] don't wait on disk to start on resume |
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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
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