Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751819Ab1FGKUw (ORCPT ); Tue, 7 Jun 2011 06:20:52 -0400 Received: from mailout-de.gmx.net ([213.165.64.22]:37782 "HELO mailout-de.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750990Ab1FGKUv (ORCPT ); Tue, 7 Jun 2011 06:20:51 -0400 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX1/2lrV7FLb20hdg3s1U2Sj8xdSfY78xNOo7re56y2 TZiHIxeSZ6/7yf Subject: Re: [PATCH] sched: remove redundant check in select_task_rq_fair From: Mike Galbraith To: Peter Zijlstra Cc: "Nikunj A. Dadhania" , mingo@elte.hu, linux-kernel@vger.kernel.org, Suresh Siddha In-Reply-To: <1307441361.2322.239.camel@twins> References: <20110607094821.29969.50197.stgit@IBM-009124035060.in.ibm.com> <1307440414.2322.236.camel@twins> <1307441361.2322.239.camel@twins> Content-Type: text/plain; charset="UTF-8" Date: Tue, 07 Jun 2011 12:20:43 +0200 Message-ID: <1307442043.3625.6.camel@marge.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1146 Lines: 30 On Tue, 2011-06-07 at 12:09 +0200, Peter Zijlstra wrote: > On Tue, 2011-06-07 at 15:34 +0530, Nikunj A. Dadhania wrote: > > On Tue, 07 Jun 2011 11:53:34 +0200, Peter Zijlstra wrote: > > > On Tue, 2011-06-07 at 15:18 +0530, Nikunj A. Dadhania wrote: > > > > When balancing for wakeup affinity, a redundant check can removed. > > > > > > Yes, tempting, but no, now you've got an extra call to wake_affine(), > > > which is more expensive. > > > Ah, got that. How about this, it is more readable. Other options would > > be to add a comment. > > > - if (cpu == prev_cpu || wake_affine(affine_sd, p, sync)) > > + if (cpu != prev_cpu && wake_affine(affine_sd, p, sync)) > > prev_cpu = cpu; > > I guess that depends on which way your head is wired and how strong your > boolean algebra is.. Suresh, Mike any preference? I don't much care > either way. Me either. -Mike -- 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/