From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: 0.11: SMP guests using one host CPU only? Date: Tue, 20 Oct 2009 22:16:03 +0900 Message-ID: <4ADDB813.5010004@redhat.com> References: <4ADD7CFF.1080003@wpkg.org> <4ADD85D3.7000004@redhat.com> <4ADD8E56.5030409@wpkg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Tomasz Chmielewski Return-path: Received: from mx1.redhat.com ([209.132.183.28]:35140 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751863AbZJTNQD (ORCPT ); Tue, 20 Oct 2009 09:16:03 -0400 In-Reply-To: <4ADD8E56.5030409@wpkg.org> Sender: kvm-owner@vger.kernel.org List-ID: On 10/20/2009 07:17 PM, Tomasz Chmielewski wrote: > Avi Kivity wrote: >> On 10/20/2009 06:03 PM, Tomasz Chmielewski wrote: >>> On a 8 CPU host, I created a guest with 4 CPUs (-smp 4). >>> >>> Unfortunately, the guest only uses one host CPU. >>> For example, running "cat /dev/urandom | gzip -9 >/dev/null &" >>> several times on this guest causes load on only one host CPU. >>> >>> Is it expected? >> >> No. What does 'top -H' show? > > In the guest - 4 CPUs with ~100% usage each (when I press "1"), > otherwise, in the task list, multiple "cat" processes taking most CPU > time (as it reads from /dev/urandom). > > > In the host - qemu-system-x86 (one process/thread) taking ~100% CPU; > when I press "1", I see only one CPU is used 100%, 7 other CPUs are > more or less not used. > I meant, how many qemu threads are there, and how much cpu does each take? -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.