From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: KVM Test report, kernel 647e9e... qemu 7811d4... Date: Sun, 28 Mar 2010 12:09:56 +0300 Message-ID: <4BAF1CE4.8030401@redhat.com> References: <4BAA2D0E.1010606@redhat.com> <4BAC8445.4000205@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "kvm@vger.kernel.org" To: "Hao, Xudong" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:30601 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753907Ab0C1JJ7 (ORCPT ); Sun, 28 Mar 2010 05:09:59 -0400 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 03/28/2010 12:03 PM, Hao, Xudong wrote: > Avi Kivity wrote: > >> You need to fold the -hda parameter into -driver, so the whole command >> line becomes >> >> qemu-system-x86_64 -m 512 -smp 4 -net >> nic,macaddr=00:16:3e:79:0c:db,model=rtl8139 -net >> tap,script=/etc/kvm/qemu-ifup -drive >> file=/share/ltp_guest.img,cache=writeback >> >> >> -hda is deprecated, it forces cache=writethrough. >> > Okay, cache=writeback can improve 28% performance of diotest, it cost 135 seconds which cost 182 sconds with cache=writethrough. > But in the report of bug, there was 2.53 times downgrade performance than before, so maybe still need somewhere tuning. > > Can you try creating the image with qemu-img create -f qcow2 -o cluster_size=4096 guest.img That reduces the cluster size to 4096, maybe that helps diotest. -- error compiling committee.c: too many arguments to function