From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: vCPU scalability for linux VMs Date: Wed, 05 May 2010 11:43:32 +0300 Message-ID: <4BE12FB4.1090303@redhat.com> References: <1815416666.20100504184534@istomin.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: Alec Istomin Return-path: Received: from mx1.redhat.com ([209.132.183.28]:60596 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933783Ab0EEInf (ORCPT ); Wed, 5 May 2010 04:43:35 -0400 In-Reply-To: <1815416666.20100504184534@istomin.de> Sender: kvm-owner@vger.kernel.org List-ID: On 05/05/2010 04:45 AM, Alec Istomin wrote: > Gentlemen, > Reaching out with a non-development question, sorry if it's not > appropriate here. > > I'm looking for a way to improve Linux SMP VMs performance under KVM. > > My preliminary results show that single vCPU Linux VMs perform up to 10 > times better than 4vCPU Linux VMs (consolidated performance of 8 VMs on > 8 core pre-Nehalem server). I suspect that I'm missing something major > and look for any means that can help improve SMP VMs performance. > > > So you have a total of 32 vcpus on 8 cores? This is known to be problematic. You may see some improvement by enabling hyperthreading. There is ongoing work to improve this. -- error compiling committee.c: too many arguments to function