Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755964Ab1EDXrx (ORCPT ); Wed, 4 May 2011 19:47:53 -0400 Received: from www.linutronix.de ([62.245.132.108]:43909 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755146Ab1EDXrw (ORCPT ); Wed, 4 May 2011 19:47:52 -0400 Date: Thu, 5 May 2011 01:47:44 +0200 (CEST) From: Thomas Gleixner To: Andi Kleen cc: Dave Kleikamp , Chris Mason , Peter Zijlstra , Tim Chen , linux-kernel@vger.kernel.org, lenb@kernel.org, paulmck@us.ibm.com Subject: Re: idle issues running sembench on 128 cpus In-Reply-To: <20110504234241.GD2925@one.firstfloor.org> Message-ID: References: <4DC1C95B.4040706@gmail.com> <20110504230349.GC2925@one.firstfloor.org> <20110504234241.GD2925@one.firstfloor.org> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1224 Lines: 36 On Thu, 5 May 2011, Andi Kleen wrote: > On Thu, May 05, 2011 at 01:29:49AM +0200, Thomas Gleixner wrote: > > That makes sense, but merging the timeouts race free will be a real > > PITA. > > For this case one could actually use a spinlock between the siblings. > That shouldn't be a problem as long as it's not a global spinlock. Care to give it a try ? > > > Also if it's HPET you could actually use multiple independent HPET channels. > > > I remember us discussing this a long time ago... Not sure if it's worth > > > it, but it may be a small relief. > > > > Multiple broadcast devices. That sounds still horrible :) > > > It would cut contention in half or more at least. Not great, > but sometimes you take everything you can get. To a certain degree. If the code pain is larger than the benefit ... > Here's a new patch without the raw. Boots on my Westmere. > + cpu = raw_smp_processor_id(); Hmm. quilt refresh perhaps ? I know that feeling :) Thanks, tglx -- 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/