From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fabian Deutsch Subject: Re: KVM performance Date: Sat, 27 Jan 2007 04:11:37 +0100 Message-ID: <1169867497.5493.7.camel@localhost.localdomain> References: <1169857267.30807.44.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: tim.c.chen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org Return-path: In-Reply-To: <1169857267.30807.44.camel-bi+AKbBUZKY6gyzm1THtWbp2dZbC/Bob@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Hey, > Hi, > > I did some testing of KVM on my woodcrest machine. And I found that > building a 2.6.19 kernel with identical configuration takes 845 sec on a > guest and 210 sec on the host. So the compile is about 4X slower on the > guest :( I wasn't able to compile some vanilla kernels, but i did two loops on the host and guest. First, with nearly no hd read/writes. # time (for I in $(seq 1 100000) ; do echo $I > /dev/null ; done) host: 3.7s 100% guest: 4.1s 110% And a second one with hd read/writes (might have a look at strace of date, tells you that date open/closes a lot of files): # time (for I in $(seq 1 1000) ; do date > /dev/null ; done) host: 1s 100% guest: 14s 1400% i don't really know how much those tests say, but: It seems as if the hd access is the bottleneck :) fabian ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV