From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: Async suspend-resume patch w/ completions (was: Re: Async suspend-resume patch w/ rwsems) Date: Thu, 17 Dec 2009 21:36:36 +0100 Message-ID: <200912172136.36277.rjw@sisk.pl> References: Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from ogre.sisk.pl ([217.79.144.158]:35491 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759915AbZLQUf5 (ORCPT ); Thu, 17 Dec 2009 15:35:57 -0500 In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Alan Stern Cc: Linus Torvalds , Zhang Rui , LKML , ACPI Devel Maling List , pm list On Thursday 17 December 2009, Alan Stern wrote: > 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) Plus ACPI battery. > then we would reap close to the maximum benefit -- providing: > > async threads are started in a first pass without waiting > for synchronous devices, and Agreed. > It's not clear that making all these types of devices async will really > work, but it's worth testing. I'm working on it. Rafael