Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752846Ab1FGKJd (ORCPT ); Tue, 7 Jun 2011 06:09:33 -0400 Received: from merlin.infradead.org ([205.233.59.134]:47901 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752744Ab1FGKJc convert rfc822-to-8bit (ORCPT ); Tue, 7 Jun 2011 06:09:32 -0400 Subject: Re: [PATCH] sched: remove redundant check in select_task_rq_fair From: Peter Zijlstra To: "Nikunj A. Dadhania" Cc: mingo@elte.hu, linux-kernel@vger.kernel.org, Suresh Siddha , Mike Galbraith In-Reply-To: References: <20110607094821.29969.50197.stgit@IBM-009124035060.in.ibm.com> <1307440414.2322.236.camel@twins> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Tue, 07 Jun 2011 12:09:21 +0200 Message-ID: <1307441361.2322.239.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1031 Lines: 23 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. -- 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/