From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755719Ab3BDO16 (ORCPT ); Mon, 4 Feb 2013 09:27:58 -0500 Received: from mail-pa0-f41.google.com ([209.85.220.41]:33433 "EHLO mail-pa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755670Ab3BDO1y (ORCPT ); Mon, 4 Feb 2013 09:27:54 -0500 Message-ID: <510FC560.6020002@intel.com> Date: Mon, 04 Feb 2013 22:27:44 +0800 From: Aaron Lu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.12) Gecko/20130109 Thunderbird/10.0.12 MIME-Version: 1.0 To: "dbasehore ." CC: Alan Stern , James Bottomley , Jeff Garzik , linux-ide@vger.kernel.org, linux-kernel , SCSI development list , Linux-pm mailing list Subject: Re: [PATCH 1/2] don't wait on disk to start on resume References: <510E025A.9000103@intel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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