From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: VM performance issue in KVM guests. Date: Thu, 15 Apr 2010 15:33:18 +0200 Message-ID: <1271338398.1674.13.camel@laptop> References: <4BC0D125.9050108@redhat.com> <4BC2C07B.4040607@redhat.com> <4BC6CBE3.8020207@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit 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 To: Avi Kivity Return-path: Received: from bombadil.infradead.org ([18.85.46.34]:46478 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753567Ab0DONdV (ORCPT ); Thu, 15 Apr 2010 09:33:21 -0400 Received: from e35131.upc-e.chello.nl ([213.93.35.131] helo=dyad.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.69 #1 (Red Hat Linux)) id 1O2PC5-0004ND-Fx for kvm@vger.kernel.org; Thu, 15 Apr 2010 13:33:21 +0000 In-Reply-To: <4BC6CBE3.8020207@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: 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. Para virt kernels could possibly extend the thing by also checking to see if the owner's vcpu is running.