From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: First performance numbers Date: Fri, 19 Sep 2008 18:30:50 -0700 Message-ID: <48D4524A.80902@redhat.com> References: <1221658886-14109-1-git-send-email-agraf@suse.de> <20080919214824.GA11410@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Alexander Graf , kvm@vger.kernel.org, joro@8bytes.org, anthony@codemonkey.ws, avi@qumranet.com To: Joerg Roedel Return-path: Received: from mx2.redhat.com ([66.187.237.31]:53206 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752721AbYITBa4 (ORCPT ); Fri, 19 Sep 2008 21:30:56 -0400 In-Reply-To: <20080919214824.GA11410@amd.com> Sender: kvm-owner@vger.kernel.org List-ID: Joerg Roedel wrote: > Ok, here are some performance numbers for nested svm. I ran kernbench -M > on a virtual machine with 4G RAM and 1 VCPU (since nesting SMP guests > do currently not work). I measured simple virtualization with a shadow > paging guest on bare metal and within a nested guest (same guest image) > on a nested paging enabled first level guest. > > | Shadow Guest (100%) | Nested Guest (X) | X > -----------------+---------------------+-------------------+-------- > Elapsed Time | 553.244 (1.21208) | 1185.95 (20.0365) | 214.363% > User Time | 407.728 (0.987279) | 520.434 (8.55643) | 127.642% > System Time | 144.828 (0.480645) | 664.528 (11.6648) | 458.839% > Percent CPU | 99 (0) | 99 (0) | 100.000% > Context Switches | 98265.2 (183.001) | 220015 (3302.74) | 223.899% > Sleeps | 49397.8 (31.0274) | 49460.2 (364.84) | 100.126% > > So we have an overall slowdown in the first nesting level of more than > 50%. Mostly because we spend so much time in the system level. Seems > there is some work to do for performance improvements :-) > > Do you have kvm_stat output for the two cases? Also interesting to run kvm_stat on both guest and host. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.