From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Re: 0.11: SMP guests using one host CPU only? Date: Tue, 20 Oct 2009 15:19:44 +0200 Message-ID: <4ADDB8F0.5010709@wpkg.org> References: <4ADD7CFF.1080003@wpkg.org> <4ADD85D3.7000004@redhat.com> <4ADD8E56.5030409@wpkg.org> <4ADDB813.5010004@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from [78.111.66.105] ([78.111.66.105]:52992 "EHLO mx03.syneticon.net" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752125AbZJTNUG (ORCPT ); Tue, 20 Oct 2009 09:20:06 -0400 In-Reply-To: <4ADDB813.5010004@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > 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? There is only one qemu thread for the 4-cpu guest. -- Tomasz Chmielewski http://wpkg.org