Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756012Ab0FAThG (ORCPT ); Tue, 1 Jun 2010 15:37:06 -0400 Received: from one.firstfloor.org ([213.235.205.2]:37541 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753700Ab0FAThE (ORCPT ); Tue, 1 Jun 2010 15:37:04 -0400 Date: Tue, 1 Jun 2010 21:36:59 +0200 From: Andi Kleen To: john cooper Cc: Avi Kivity , Andi Kleen , Gleb Natapov , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, hpa@zytor.com, mingo@elte.hu, npiggin@suse.de, tglx@linutronix.de, mtosatti@redhat.com, john cooper Subject: Re: [PATCH] use unfair spinlock when running on hypervisor. Message-ID: <20100601193659.GC11880@basil.fritz.box> References: <20100601093515.GH24302@redhat.com> <87sk56ycka.fsf@basil.nowhere.org> <20100601162414.GA6191@redhat.com> <20100601163807.GA11880@basil.fritz.box> <4C053ACC.5020708@redhat.com> <4C05493F.1040107@third-harmonic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4C05493F.1040107@third-harmonic.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 680 Lines: 17 > Collecting the contention/usage statistics on a per spinlock > basis seems complex. I believe a practical approximation > to this are adaptive mutexes where upon hitting a spin > time threshold, punt and let the scheduler reconcile fairness. That would probably work, except: how do you get the adaptive spinlock into a paravirt op without slowing down a standard kernel? -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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/