From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: sync guest calls made async on host - SQLite performance Date: Tue, 29 Sep 2009 13:57:07 -0500 Message-ID: <4AC25883.4040409@codemonkey.ws> References: <4ABA45BE.1080008@gmail.com> <4ABB5BAD.3000007@redhat.com> <4ABB6E07.60909@redhat.com> <4ABC6FC5.6080007@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Matthew Tippett , kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mail-qy0-f174.google.com ([209.85.221.174]:62988 "EHLO mail-qy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753916AbZI2TDK (ORCPT ); Tue, 29 Sep 2009 15:03:10 -0400 Received: by qyk4 with SMTP id 4so4231543qyk.33 for ; Tue, 29 Sep 2009 12:03:14 -0700 (PDT) In-Reply-To: <4ABC6FC5.6080007@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > On 09/24/2009 10:49 PM, Matthew Tippett wrote: >> The test itself is a simple usage of SQLite. It is stock KVM as >> available in 2.6.31 on Ubuntu Karmic. So it would be the environment, >> not the test. >> >> So assuming that KVM upstream works as expected that would leave >> either 2.6.31 having an issue, or Ubuntu having an issue. >> >> Care to make an assertion on the KVM in 2.6.31? Leaving only Ubuntu's >> installation. >> > > kvm has nothing to do with it, it's purely qemu. For a long time qemu > has defaulted to write-through cacheing. This can be overridden and > maybe that's what Ubuntu or Phoronix do. > >> Can some KVM developers attempt to confirm that a 'correctly' >> configured KVM will not demonstrate this behaviour? >> http://www.phoronix-test-suite.com/ (or is already available in newer >> distributions of Fedora, openSUSE and Ubuntu. >> > > A correctly configured kvm will not demonstrate this behaviour. It was a very old kvm version (kvm-84). But of course, the version of kvm is not mentioned on the Phoronix site... Regards, Anthony Liguori