Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965220AbZLQUGO (ORCPT ); Thu, 17 Dec 2009 15:06:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759703AbZLQUGM (ORCPT ); Thu, 17 Dec 2009 15:06:12 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:38932 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1757870AbZLQUGK (ORCPT ); Thu, 17 Dec 2009 15:06:10 -0500 Date: Thu, 17 Dec 2009 15:06:06 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: "Rafael J. Wysocki" cc: Linus Torvalds , Zhang Rui , LKML , ACPI Devel Maling List , pm list Subject: Re: Async suspend-resume patch w/ completions (was: Re: Async suspend-resume patch w/ rwsems) In-Reply-To: <200912170249.00676.rjw@sisk.pl> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1591 Lines: 40 On Thu, 17 Dec 2009, Rafael J. Wysocki wrote: > That actually is correct. On the nx6325 suspend is totally dominated by disk > spindown, almost everything else is negligible compared to it (well, except for > the audio), so we can't go down below 1 s during suspend on this box. > > On the Wind, disk spindown time is comparable with serio suspend time, > so at least in principle we should be able to get .5 s suspend on this box - > if the disk spindown in async. > > In turn, the resume on the Wind is dominated by disk spinup, so we can't > go below 1.5 s on this box during resume (notice that the "async+extra" > approach brings us close to this limit, although we could save .5 s more in > principle by making more devices async). > > Resume on the nx6325 is a different story, though, as it is dominated by USB > and PCI devices, so marking those as async would probably bring us close to > the limit. The implications seem pretty clear. If the following sorts of devices were async: USB (devices and interfaces), PCI, serio, SCSI (hosts, targets, devices) then we would reap close to the maximum benefit -- providing: async threads are started in a first pass without waiting for synchronous devices, and It's not clear that making all these types of devices async will really work, but it's worth testing. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/