From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752243Ab1HZWst (ORCPT ); Fri, 26 Aug 2011 18:48:49 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:34473 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750715Ab1HZWss (ORCPT ); Fri, 26 Aug 2011 18:48:48 -0400 Subject: Re: [PATCH 2/3] broadcast-tick: Move oneshot broadcast mask to per cpu variables From: Eric Dumazet To: Andi Kleen Cc: tglx@linutronix.de, linux-kernel@vger.kernel.org, tim.c.chen@linux.intel.com, Andi Kleen In-Reply-To: <1314397924-10236-2-git-send-email-andi@firstfloor.org> References: <1314397924-10236-1-git-send-email-andi@firstfloor.org> <1314397924-10236-2-git-send-email-andi@firstfloor.org> Content-Type: text/plain; charset="UTF-8" Date: Sat, 27 Aug 2011 00:48:42 +0200 Message-ID: <1314398922.3036.2.camel@edumazet-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le vendredi 26 août 2011 à 15:32 -0700, Andi Kleen a écrit : > From: Andi Kleen > > Avoid a global cache line hotspot in the oneshot cpu mask. Maintain > this information in per cpu variables instead. > > Signed-off-by: Andi Kleen > --- > > -/* FIXME: use cpumask_var_t. */ > -static DECLARE_BITMAP(tick_broadcast_oneshot_mask, NR_CPUS); > +struct broadcast_cpu_state { > + int need_oneshot; > +} ____cacheline_aligned; > +static DEFINE_PER_CPU(struct broadcast_cpu_state, state); static DEFINE_PER_CPU_ALIGNED(...) It avoids adding an alignment requirement on .data..percpu