Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751821Ab2B0JHB (ORCPT ); Mon, 27 Feb 2012 04:07:01 -0500 Received: from mail-qy0-f174.google.com ([209.85.216.174]:63302 "EHLO mail-qy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750704Ab2B0JG7 (ORCPT ); Mon, 27 Feb 2012 04:06:59 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of yong.zhang0@gmail.com designates 10.224.194.195 as permitted sender) smtp.mail=yong.zhang0@gmail.com; dkim=pass header.i=yong.zhang0@gmail.com Date: Mon, 27 Feb 2012 17:06:46 +0800 From: Yong Zhang To: "Paul E. McKenney" Cc: Venki Pallipadi , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Suresh Siddha , Aaron Durbin , Paul Turner , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Extend mwait idle to optimize away CAL and RES interrupts to an idle CPU -v1 Message-ID: <20120227090646.GA1112@zhy> Reply-To: Yong Zhang References: <1329957415-15239-1-git-send-email-venki@google.com> <1329989454.24994.57.camel@twins> <20120224054150.GA17543@zhy> <20120226013253.GN2393@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20120226013253.GN2393@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1226 Lines: 30 On Sat, Feb 25, 2012 at 05:32:53PM -0800, Paul E. McKenney wrote: > On Fri, Feb 24, 2012 at 01:41:50PM +0800, Yong Zhang wrote: > > On Thu, Feb 23, 2012 at 11:34:11AM -0800, Venki Pallipadi wrote: > > > On Thu, Feb 23, 2012 at 1:30 AM, Peter Zijlstra wrote: > > > > Why not scheduler_ipi()? > > > > > > Was trying to avoid irq_enter/exit. As the work here is done in idle > > > thread context, I though we could avoid enter/exit. > > > > It seems we could not. > > At least RCU need it, see commit c5d753a55, otherwise we will get > > warning like 'RCU used illegally from extended quiescent state!' > > If the use is tracing, then Steven Rostedt's patchset plus use of his > _rcuidle() tracing variants handles this: > > https://lkml.org/lkml/2012/2/7/231 > > If this is instead algorithmic use of RCU, a set of patches I have queued > up for 3.4 will be required. scheduler_ipi() doing more than tracing. Will look at your patches :) Thanks, Yong -- 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/