Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755873AbaAGIc0 (ORCPT ); Tue, 7 Jan 2014 03:32:26 -0500 Received: from mail-oa0-f48.google.com ([209.85.219.48]:38134 "EHLO mail-oa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755096AbaAGIcZ (ORCPT ); Tue, 7 Jan 2014 03:32:25 -0500 MIME-Version: 1.0 In-Reply-To: <20140106163123.GN31570@twins.programming.kicks-ass.net> References: <20131105222752.GD16117@laptop.programming.kicks-ass.net> <1387372431-2644-1-git-send-email-vincent.guittot@linaro.org> <52B87149.4010801@arm.com> <20140106163123.GN31570@twins.programming.kicks-ass.net> From: Vincent Guittot Date: Tue, 7 Jan 2014 09:32:04 +0100 Message-ID: Subject: Re: [RFC] sched: CPU topology try To: Peter Zijlstra Cc: Dietmar Eggemann , "linux-kernel@vger.kernel.org" , "mingo@kernel.org" , "pjt@google.com" , Morten Rasmussen , "cmetcalf@tilera.com" , "tony.luck@intel.com" , "alex.shi@linaro.org" , "preeti@linux.vnet.ibm.com" , "linaro-kernel@lists.linaro.org" , "paulmck@linux.vnet.ibm.com" , "corbet@lwn.net" , "tglx@linutronix.de" , "len.brown@intel.com" , "arjan@linux.intel.com" , "amit.kucheria@linaro.org" , "james.hogan@imgtec.com" , "schwidefsky@de.ibm.com" , "heiko.carstens@de.ibm.com" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6 January 2014 17:31, Peter Zijlstra wrote: > On Mon, Jan 06, 2014 at 02:41:31PM +0100, Vincent Guittot wrote: >> IMHO, these settings will disappear sooner or later, as an example the >> idle/busy _idx are going to be removed by Alex's patch. > > Well I'm still entirely unconvinced by them.. > > removing the cpu_load array makes sense, but I'm starting to doubt the > removal of the _idx things.. I think we want to retain them in some > form, it simply makes sense to look at longer term averages when looking > at larger CPU groups. > > So maybe we can express the things in log_2(group-span) or so, but we > need a working replacement for the cpu_load array. Ideally some > expression involving the blocked load. Using the blocked load can surely give benefit in the load balance because it gives a view of potential load on a core but it still decay with the same speed than runnable load average so it doesn't solve the issue for longer term average. One way is to have a runnable average load with longer time window > > Its another one of those things I need to ponder more :-) -- 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/