From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753397AbaFXMSJ (ORCPT ); Tue, 24 Jun 2014 08:18:09 -0400 Received: from mail-we0-f177.google.com ([74.125.82.177]:63206 "EHLO mail-we0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751774AbaFXMSH (ORCPT ); Tue, 24 Jun 2014 08:18:07 -0400 Message-ID: <1403612280.29711.115.camel@marge.simpson.net> Subject: Re: [PATCH] sched/idle: Drop !! while calculating 'broadcast' From: Mike Galbraith To: Peter Zijlstra Cc: Viresh Kumar , mingo@redhat.com, linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org Date: Tue, 24 Jun 2014 14:18:00 +0200 In-Reply-To: <20140624080347.GL13930@laptop.programming.kicks-ass.net> References: <0dfbe2976aa108c53e08d3477ea90f6360c1f54c.1403584026.git.viresh.kumar@linaro.org> <20140624080347.GL13930@laptop.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2014-06-24 at 10:03 +0200, Peter Zijlstra wrote: > On Tue, Jun 24, 2014 at 10:01:01AM +0530, Viresh Kumar wrote: > > We don't need 'broadcast' to be set to 'zero or one', but to 'zero or non-zero' > > and so the extra operation to convert it to 'zero or one' can be skipped. > > > > Also change type of 'broadcast' to unsigned int, i.e. type of > > drv->states[*].flags. > > All true; but does it change anything? That is, does your compiler > generate better code because of this? x86_64 gcc-4.8.3 made 1 less instruction, a shift. -Mike