From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH 00/20] x86: ticket lock rewrite and paravirtualization Date: Mon, 15 Nov 2010 22:08:32 +0100 Message-ID: <1289855312.2109.555.camel@laptop> References: <4CDDBBD3.5050903@zytor.com> <4CDDBCE4.80906@goop.org> <4CDDBDB5.8000800@zytor.com> <4CE1915F.60507@goop.org> <4CE1920F.5000509@zytor.com> <1289852088.2109.553.camel@laptop> <4CE19FD1.2000804@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4CE19FD1.2000804@goop.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jeremy Fitzhardinge Cc: Xen-devel , Mathieu Desnoyers , Srivatsa@smtp1.linux-foundation.org, Linux@smtp1.linux-foundation.org, Linux Kernel Mailing List , Jan Beulich , Virtualization , Vaddagiri , Kivity , "H. Peter Anvin" , Avi@smtp1.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org On Mon, 2010-11-15 at 13:02 -0800, Jeremy Fitzhardinge wrote: > > As a heuristic, it shouldn't be too bad performancewise, since > (handwaving) if ticketholder N has entered the slowpath, then its likely > that N+1 will as well. Yes, esp. if the whole slow unlock path takes more cycles than you spin for to begin with. I think this approach is definitely worth trying. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758536Ab0KOVIk (ORCPT ); Mon, 15 Nov 2010 16:08:40 -0500 Received: from casper.infradead.org ([85.118.1.10]:42022 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758515Ab0KOVIj convert rfc822-to-8bit (ORCPT ); Mon, 15 Nov 2010 16:08:39 -0500 Subject: Re: [PATCH 00/20] x86: ticket lock rewrite and paravirtualization From: Peter Zijlstra To: Jeremy Fitzhardinge Cc: "H. Peter Anvin" , Linux Kernel Mailing List , Jan Beulich , Avi Kivity , Xen-devel , Linux Virtualization , Srivatsa Vaddagiri , Mathieu Desnoyers In-Reply-To: <4CE19FD1.2000804@goop.org> References: <4CDDBBD3.5050903@zytor.com> <4CDDBCE4.80906@goop.org> <4CDDBDB5.8000800@zytor.com> <4CE1915F.60507@goop.org> <4CE1920F.5000509@zytor.com> <1289852088.2109.553.camel@laptop> <4CE19FD1.2000804@goop.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Mon, 15 Nov 2010 22:08:32 +0100 Message-ID: <1289855312.2109.555.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2010-11-15 at 13:02 -0800, Jeremy Fitzhardinge wrote: > > As a heuristic, it shouldn't be too bad performancewise, since > (handwaving) if ticketholder N has entered the slowpath, then its likely > that N+1 will as well. Yes, esp. if the whole slow unlock path takes more cycles than you spin for to begin with. I think this approach is definitely worth trying.