From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755903AbaGVPrS (ORCPT ); Tue, 22 Jul 2014 11:47:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:18290 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755620AbaGVPrR (ORCPT ); Tue, 22 Jul 2014 11:47:17 -0400 Message-ID: <53CE875F.5040007@redhat.com> Date: Tue, 22 Jul 2014 11:46:39 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Peter Zijlstra CC: linux-kernel@vger.kernel.org, Kirill Tkhai , Tim Chen , Nicolas Pitre , mingo@kernel.org, pjt@google.com Subject: Re: [PATCH] sched: update last_balance only when actually balanced References: <20140722022121.4589c63b@annuminas.surriel.com> <20140722120445.GB3935@laptop> In-Reply-To: <20140722120445.GB3935@laptop> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 07/22/2014 08:04 AM, Peter Zijlstra wrote: >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index >> 45943b2..4f7fee2 100644 --- a/kernel/sched/fair.c +++ >> b/kernel/sched/fair.c @@ -7187,7 +7187,9 @@ static void >> rebalance_domains(struct rq *rq, enum cpu_idle_type idle) */ idle >> = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE; } - sd->last_balance >> = jiffies; + /* Only update if we actually balanced. */ + if >> (continue_balancing) + sd->last_balance = jiffies; interval = >> get_sd_balance_interval(sd, idle != CPU_IDLE); } if >> (need_serialize) > > Did you actually see any difference with this patch? > > The reason I'm asking is that the sched_domains are per cpu, so > the above assignment is only visible to that particular cpu, not > other cpus. It was past 2AM, it may have been a placebo effect :) Back to the drawing board, to figure out why the load balancing code is not working quite as expected... - -- All rights reversed -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJTzodfAAoJEM553pKExN6DR3oH+wVSYjVu6eV1tzaDLw2xSvSl rO8hC9GtIf3LX8NVp/UTVkQXt7wWDLcpV4f+AO9+ikB9Dk5YD9wfTF6vhZVrP8GV Zjpd3HvO/H3RYomyDXLbocjZ97JsXBF7kxRWmYw0kixUIzhdt/sZKGc46aQXPnGy BfcGcYYbBKeFr9rrYTTvHwN5XVB1ZMZBEWiH/6baXGgZ5V/rTdcZDw0VGXailpbn eM5j33B9gCE6bYxD1uCrfZXdaO4BORCkiqfncpSVqLnl9k7B9HbY44bcbqht/qHy B/F/7+imlvAfhwfQAhj8EYomaAT2GI8m6Ab7frxagJURJ1McU3r+2dgkkhsSqP8= =QnLG -----END PGP SIGNATURE-----