Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758788Ab0FBV6c (ORCPT ); Wed, 2 Jun 2010 17:58:32 -0400 Received: from mail-pv0-f174.google.com ([74.125.83.174]:64354 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758647Ab0FBV6b convert rfc822-to-8bit (ORCPT ); Wed, 2 Jun 2010 17:58:31 -0400 MIME-Version: 1.0 In-Reply-To: <20100602133910.GA9106@gvim.org> References: <201005312338.55109.rjw@sisk.pl> <20100531232617.GF31155@gvim.org> <20100601090737.4bc243d9@schatten.dmk.lab> <20100601140519.GC1281@gvim.org> <20100602133910.GA9106@gvim.org> Date: Wed, 2 Jun 2010 14:58:30 -0700 Message-ID: Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) From: =?ISO-8859-1?Q?Arve_Hj=F8nnev=E5g?= To: markgross@thegnar.org Cc: Florian Mickler , 640e9920@gmail.com, "Rafael J. Wysocki" , Alan Stern , Peter Zijlstra , Linux PM , Brian Swetland , Alan Cox , Matthew Garrett , Thomas Gleixner , LKML , Ingo Molnar Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2106 Lines: 47 2010/6/2 mark gross <640e9920@gmail.com>: > 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. > The list is not short. You have all the inactive and active constraints on the same list. If you change it to a two level list though, the list of unique values (which is the list you have to walk) may be short enough for a tree to be overkill. -- Arve Hj?nnev?g -- 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/