Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752799Ab1FGKE4 (ORCPT ); Tue, 7 Jun 2011 06:04:56 -0400 Received: from e23smtp03.au.ibm.com ([202.81.31.145]:45490 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752484Ab1FGKEz (ORCPT ); Tue, 7 Jun 2011 06:04:55 -0400 From: "Nikunj A. Dadhania" To: Peter Zijlstra Cc: mingo@elte.hu, linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched: remove redundant check in select_task_rq_fair In-Reply-To: <1307440414.2322.236.camel@twins> References: <20110607094821.29969.50197.stgit@IBM-009124035060.in.ibm.com> <1307440414.2322.236.camel@twins> User-Agent: Notmuch/0.3.1-59-g676d251 (http://notmuchmail.org) Emacs/23.2.1 (x86_64-redhat-linux-gnu) Date: Tue, 07 Jun 2011 15:34:48 +0530 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1197 Lines: 30 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. Signed-off-by: Nikunj A. Dadhania --- kernel/sched_fair.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 433491c..354e26b 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1753,7 +1753,7 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) } if (affine_sd) { - if (cpu == prev_cpu || wake_affine(affine_sd, p, sync)) + if (cpu != prev_cpu && wake_affine(affine_sd, p, sync)) prev_cpu = cpu; -- 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/