Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754364Ab0DQTFE (ORCPT ); Sat, 17 Apr 2010 15:05:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:7492 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753635Ab0DQTFB (ORCPT ); Sat, 17 Apr 2010 15:05:01 -0400 Message-ID: <4BCA0646.1000603@redhat.com> Date: Sat, 17 Apr 2010 22:04:38 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.0.4-1.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: Peter Zijlstra CC: Srivatsa Vaddagiri , "Zhang, Xiantao" , "kvm@vger.kernel.org" , Marcelo Tosatti , "Yang, Xiaowei" , "Dong, Eddie" , "Li, Xin" , Ingo Molnar , Mike Galbraith , Linux Kernel Mailing List , vatsa@linux.vnet.ibm.com Subject: Re: VM performance issue in KVM guests. References: <4BC0D125.9050108@redhat.com> <4BC2C07B.4040607@redhat.com> <4BC6CBE3.8020207@redhat.com> <1271338398.1674.13.camel@laptop> In-Reply-To: <1271338398.1674.13.camel@laptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 923 Lines: 28 On 04/15/2010 04:33 PM, Peter Zijlstra wrote: > On Thu, 2010-04-15 at 11:18 +0300, Avi Kivity wrote: > >> Certainly that has even greater potential for Linux guests. Note that >> we spin on mutexes now, so we need to prevent preemption while the lock >> owner is running. >> > either that, or disable spinning on (para) virt kernels. What would you do instead? Note we can't disable spinning on Windows or pre 2.6.36 kernels. > Para virt > kernels could possibly extend the thing by also checking to see if the > owner's vcpu is running. > Certainly that's worth doing. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. -- 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/