From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: slow guest performance with build load, looking for ideas Date: Mon, 15 Jun 2009 17:24:14 +0300 Message-ID: <4A36598E.5050300@redhat.com> References: <20090612210443.GA21840@sgi.com> <4A34C3D2.9020009@redhat.com> <20090615141542.GA17448@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Erik Jacobson Return-path: Received: from mx2.redhat.com ([66.187.237.31]:50267 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751506AbZFOOYJ (ORCPT ); Mon, 15 Jun 2009 10:24:09 -0400 In-Reply-To: <20090615141542.GA17448@sgi.com> Sender: kvm-owner@vger.kernel.org List-ID: On 06/15/2009 05:15 PM, Erik Jacobson wrote: >> What is the host cpu type? On pre-Nehalem/Barcelona processors kvm has >> poor scalability in mmu intensive workloads like kernel builds. >> > > Thanks for getting back to me. > > Today is pretty booked but I'm going to go find a Nehalem system and try to > run similar tests to compare. I'll post my results to this thread. > > So if I understand what you're saying: best not to use kvm guests for build > servers with pre-Nehalem processors. > pre-Nehalem / pre-Barcelona, > 4 vcpus, yes. > Both systems I used were pre-Nehalem. Here is a cpuinfo snip from both > systems I tested on: > Yes, so I expect you're seeing contention on kvm->mmu_lock. -- error compiling committee.c: too many arguments to function