From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751519Ab3LKXOh (ORCPT ); Wed, 11 Dec 2013 18:14:37 -0500 Received: from mail.skyhub.de ([78.46.96.112]:45478 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751028Ab3LKXOd (ORCPT ); Wed, 11 Dec 2013 18:14:33 -0500 Date: Thu, 12 Dec 2013 00:14:25 +0100 From: Borislav Petkov To: "H. Peter Anvin" Cc: Ingo Molnar , Peter Zijlstra , Mike Galbraith , Thomas Gleixner , Len Brown , Linux PM list , "linux-kernel@vger.kernel.org" , Jeremy Eder , x86@kernel.org Subject: Re: 50 Watt idle power regression bisected to Linux-3.10 Message-ID: <20131211231425.GD8863@pd.tnic> References: <20131211113839.GF21683@pd.tnic> <20131211115239.GA21999@twins.programming.kicks-ass.net> <1386764955.12005.60.camel@marge.simpson.net> <20131211124352.GB21999@twins.programming.kicks-ass.net> <20131211134048.GH21683@pd.tnic> <20131211145655.GB4510@gmail.com> <20131211164318.GA2480@laptop.programming.kicks-ass.net> <20131211175036.GC12431@gmail.com> <52A8F073.9040500@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <52A8F073.9040500@zytor.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 On Wed, Dec 11, 2013 at 03:08:35PM -0800, H. Peter Anvin wrote: > So I would like to propose that we switch to using a percpu variable > which is a single cache line of nothing at all. It would only ever > be touched by MONITOR and for explicit wakeup. Hopefully that will > resolve this problem without the need for the CLFLUSH. Yep, makes a lot of sense to me to have an exclusive (overloaded meaning here :-)) cacheline only for that. And, if it works, we'll save us the penalty from the CLFLUSH too, cool. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --