From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: slow guest performance with build load, looking for ideas Date: Thu, 09 Jul 2009 10:48:49 +0300 Message-ID: <4A55A0E1.1060501@redhat.com> References: <20090612210443.GA21840@sgi.com> <4A34C3D2.9020009@redhat.com> <20090618230744.GA19307@sgi.com> <4A477B8C.2010502@redhat.com> <20090628190500.GA7347@sgi.com> <4A47E06A.7040700@redhat.com> <20090701214128.GA1380@sgi.com> <4A4C4A28.1060105@redhat.com> <4A4C80AD.7010204@redhat.com> <1246635797.13604.7.camel@blaa> <20090709023633.GB29409@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Mark McLoughlin , kvm@vger.kernel.org To: Erik Jacobson Return-path: Received: from mx2.redhat.com ([66.187.237.31]:42226 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751866AbZGIHqS (ORCPT ); Thu, 9 Jul 2009 03:46:18 -0400 In-Reply-To: <20090709023633.GB29409@sgi.com> Sender: kvm-owner@vger.kernel.org List-ID: On 07/09/2009 05:36 AM, Erik Jacobson wrote: >> Haven't followed the thread in great detail, but has anyone tried >> putting the virtio disk back into rotational mode? >> > > Hello. I haven't had a chance to try all the suggestions in the thread > so far. However, I did just run some tests with block queue rotation > settings tonight. > > For the problem where mkfs.ext3 on a virtio disk image (raw image, not > pre-allocated) the timing went from like 27 minutes for a 10gb fs down > to just over 2 minutes. So that was a huge difference. > > For the linux kernel build test, there was a difference, but less dramatic. > I'd say the performance is still below what I expected. I haven't given > up yet, there is more to try in the thread. I just wanted to post these > results. > > The HW in use is the same as in the rest of the tread, including the > virtio disk type. Since my last post, fedora 11 updates have been > applied to the system. > > Timing with the rotational stuff set to 1... > > real 14m13.015s > user 29m42.162s > sys 8m37.416s > (user + sys) / real = 2.7 > And finally, to confirm the numbers on the host with no guest running... > The same disk/filesystem, now mounted on the host instead of the guest, gave > this timing: > > real 6m13.398s > user 26m56.061s > sys 5m34.477s > (user + sys) / real = 5.2 I got 6.something in a guest! > For the guest runs, qemu command was as follows. For later tests, I will > combine the queue rotation setting with the other suggestions. > > /usr/bin/qemu-kvm -M pc -m 4096 -smp 8 -name f11-test -uuid b7b4b7e4-9c07-22aa-0c95-d5c8a24176c5 -monitor pty -pidfile /var/run/libvirt/qemu//f11-test.pid -drive file=/var/lib/libvirt/images/f11-test.img,if=virtio,index=0,boot=on -drive file=/dev/sdb,if=virtio,index=1 -drive file=/var/lib/libvirt/images/test.img,if=virtio,index=2 -net nic,macaddr=54:52:00:46:48:0e,model=virtio -net user -serial pty -parallel none -usb -usbdevice tablet -vnc cct201:1 -soundhw es1370 -redir tcp:5555::22 > Please drop -usbdevice tablet and set the host I/O scheduler to deadline. Add cache=none to the -drive options. -- error compiling committee.c: too many arguments to function