From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: AW: AW: AW: KVM performance Date: Sat, 11 Apr 2009 19:19:23 +0300 Message-ID: <49E0C30B.1000209@redhat.com> References: <133D9897FB9C5E4E9DF2779DC91E947C518348@SLFSNX.rcs.alcatel-research.de> <49D9EB48.4030709@redhat.com> <133D9897FB9C5E4E9DF2779DC91E947C51834A@SLFSNX.rcs.alcatel-research.de> <49DA2F54.8090109@redhat.com> <133D9897FB9C5E4E9DF2779DC91E947C51834E@SLFSNX.rcs.alcatel-research.de> <49DB8E8A.1090908@redhat.com> <133D9897FB9C5E4E9DF2779DC91E947C518350@SLFSNX.rcs.alcatel-research.de> <133D9897FB9C5E4E9DF2779DC91E947C518355@SLFSNX.rcs.alcatel-research.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: "BRAUN, Stefanie" Return-path: Received: from mx2.redhat.com ([66.187.237.31]:37836 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751984AbZDKQTi (ORCPT ); Sat, 11 Apr 2009 12:19:38 -0400 In-Reply-To: <133D9897FB9C5E4E9DF2779DC91E947C518355@SLFSNX.rcs.alcatel-research.de> Sender: kvm-owner@vger.kernel.org List-ID: BRAUN, Stefanie wrote: > Hello, > > now I was able to start the guest vmu with disk virtio, and some of the > tests with disk involvement even improved a bit. > But the test in which a logo is added to the video stream does not > improve. I don't know why the performance is so bad? > > Subtest: Reading video locally, adding a logo to the video stream and > then saving the video locally > Host performance: 50% > kvm process in host (top) : 99% > vlc process in vmu (top) : 99% > > > The output of kvm_stat -1 during the subtest is the following: > > efer_reload 0 0 > exits 9913473 3994 > This indicates that kvm is running in guest mode all of the time and is therefore quite efficient. Perhaps the test uses sse instructions which kvm doesn't expose? Try adding -cpu core2duo to the command line. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.