Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933737Ab0FCDKR (ORCPT ); Wed, 2 Jun 2010 23:10:17 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:58213 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933579Ab0FCDKO (ORCPT ); Wed, 2 Jun 2010 23:10:14 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:reply-to:references:mime-version :content-type:content-disposition:content-transfer-encoding :in-reply-to:user-agent; b=PkwLsL9i+XzlM5V8jAaO9G5FyXwupx7SLQLi2tMGqN4kWXyyXsd4sOBJBJ2DaW/SS0 P3L0aWtansXLyk50HKOwKh2nbrJumcPlUEYoPzIcwmBSUolWF09wrw92NuKuY0MGLNpI jKtbQBBoCmShO1BNT5aDj/SCOGACXQ7/CG83Q= Date: Wed, 2 Jun 2010 20:10:24 -0700 From: mark gross <640e9920@gmail.com> To: "Rafael J. Wysocki" Cc: markgross@thegnar.org, Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Florian Mickler , 640e9920@gmail.com, Alan Stern , Peter Zijlstra , Linux PM , Brian Swetland , Alan Cox , Matthew Garrett , Thomas Gleixner , LKML , Ingo Molnar Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) Message-ID: <20100603031024.GA11311@gvim.org> Reply-To: markgross@thegnar.org References: <20100602133910.GA9106@gvim.org> <201006030003.49486.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <201006030003.49486.rjw@sisk.pl> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2645 Lines: 57 On Thu, Jun 03, 2010 at 12:03:49AM +0200, Rafael J. Wysocki wrote: > On Wednesday 02 June 2010, mark gross wrote: > > On Tue, Jun 01, 2010 at 08:50:02PM -0700, Arve Hj?nnev?g wrote: > > > On Tue, Jun 1, 2010 at 7:05 AM, mark gross <640e9920@gmail.com> wrote: > > > > On Tue, Jun 01, 2010 at 09:07:37AM +0200, Florian Mickler wrote: > > > ... > > > >> +static void update_target_val(int pm_qos_class, s32 val) > > > >> +{ > > > >> + s32 extreme_value; > > > >> + s32 new_value; > > > >> + extreme_value = atomic_read(&pm_qos_array[pm_qos_class]->target_value); > > > >> + new_value = pm_qos_array[pm_qos_class]->comparitor(val,extreme_value); > > > >> + if (extreme_value != new_value) > > > >> + atomic_set(&pm_qos_array[pm_qos_class]->target_value,new_value); > > > >> +} > > > >> + > > > > > > > > Only works 1/2 the time, but I like the idea! > > > > It fails to get the righ answer when constraints are reduced. But, this > > > > idea is a good improvement i'll roll into the next pm_qos update! > > > > > > > > > > I think it would be a better idea to track your constraints with a > > > sorted data structure. That way you can to better than O(n) for both > > > directions. If you have a lot of constraints with the same value, it > > > may even be worthwhile to have a two stage structure where for > > > instance you use a rbtree for the unique values and list for identical > > > constraints. > > > > I don't agree, we went through this tree vrs list discussion a few times > > before in other areas of the kernel. Wherever the list tended to be > > short, a simple list wins. However; we can try it, after we have some > > metrics and stress test cases identified we can measure its effectivenes > > against. > > How many different values are there to handle? > for the current pm_qos users its tiny. I've never heard of more than a few < 10. However; for the new "interactive" class to provide suspend blocker functionality, I expect the number to be up to 20. but realistically I bet we never get more than 10ish. One constraint constraint request per module from isr to user mode. Once in user mode there would be only a few (assuming Android user space) I think just from the power HAL, input HAL, and the RIL. Still a pretty small number I don't think we need to worry about scaling as much as we need to worry about performance. --mgross -- 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/