From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dustin Kirkland Subject: Re: sync guest calls made async on host - SQLite performance Date: Wed, 7 Oct 2009 13:59:33 -0500 Message-ID: References: <4ABC6AA5.6080909@tauceti.net> <4ABF4E95.5070100@redhat.com> <4ABF5596.9050207@gmail.com> <4AC259DC.2080807@codemonkey.ws> <4AC260BB.3090906@gmail.com> <4AC27355.3090303@codemonkey.ws> <4ACCC7A1.9060303@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Anthony Liguori , Avi Kivity , RW , kvm@vger.kernel.org To: Matthew Tippett Return-path: Received: from mail-fx0-f227.google.com ([209.85.220.227]:48193 "EHLO mail-fx0-f227.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752525AbZJGTAL convert rfc822-to-8bit (ORCPT ); Wed, 7 Oct 2009 15:00:11 -0400 Received: by fxm27 with SMTP id 27so4914476fxm.17 for ; Wed, 07 Oct 2009 11:59:34 -0700 (PDT) In-Reply-To: <4ACCC7A1.9060303@gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Oct 7, 2009 at 11:53 AM, Matthew Tippett w= rote: > When you indicated that you had attempted to reproduce the problem, w= hat > mechanism did you use? =A0Was it Karmic + KVM as the host and Karmic = as > the guest? =A0What test did you use? I ran the following in several places: a) on the system running on real hardware, time dd if=3D/dev/zero of=3D$HOME/foo bs=3D1M count=3D500 524288000 bytes (524 MB) copied, 9.72614 s, 53.9 MB/s b) in an vm running on qemu-kvm-0.11 on Karmic time dd if=3D/dev/zero of=3D$HOME/foo bs=3D1M count=3D500 oflag=3Dd= irect 524288000 bytes (524 MB) copied, 31.6961 s, 16.5 MB/s c) in a vm running on kvm-84 on Jaunty time dd if=3D/dev/zero of=3D$HOME/foo bs=3D1M count=3D500 oflag=3Dd= irect 524288000 bytes (524 MB) copied, 22.2169 s, 23.6 MB/s Looking at the time it takes to write a 500MB file to a real hard disk, and then inside of the VM. If I were to experience the problem on Karmic, I would have seen this dd of a 500MB file take far, far less time than it takes to write that file to disk on the real hardware. This was not the case in my testing. > I will re-open the launchpad bug if you believe it makes sense to > continue the discussions there. Please re-open the bug if you can describe a real test case that you used to demonstrate the problem. Without being rude, it's hard for me to work from a bug that says a magazine article says that there's a bug in the Ubuntu distribution of qemu-kvm-0.11. If you can provide clear steps that you have used to experience the problem, then I will be able to take this issue seriously, reproduce it myself, and develop a fix. :-Dustin