From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1KNx5G-00042d-Mc for qemu-devel@nongnu.org; Tue, 29 Jul 2008 17:50:18 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1KNx5G-000420-27 for qemu-devel@nongnu.org; Tue, 29 Jul 2008 17:50:18 -0400 Received: from [199.232.76.173] (port=44406 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KNx5F-00041u-Ur for qemu-devel@nongnu.org; Tue, 29 Jul 2008 17:50:17 -0400 Received: from wr-out-0506.google.com ([64.233.184.227]:34343) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1KNx5F-0006pb-Kt for qemu-devel@nongnu.org; Tue, 29 Jul 2008 17:50:17 -0400 Received: by wr-out-0506.google.com with SMTP id c46so71863wra.18 for ; Tue, 29 Jul 2008 14:50:17 -0700 (PDT) Message-ID: <488F9078.1080001@codemonkey.ws> Date: Tue, 29 Jul 2008 16:49:44 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [patch 0/5][v2] qcow2: improve I/O performance with cache=off References: <20080729141352.573798859@bull.net> <488F6C3F.8050207@codemonkey.ws> <1217367328.3858.14.camel@frecb07144> In-Reply-To: <1217367328.3858.14.camel@frecb07144> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Laurent Vivier Cc: qemu-devel@nongnu.org Laurent Vivier wrote: > Le mardi 29 juillet 2008 à 14:15 -0500, Anthony Liguori a écrit : > >> Laurent Vivier wrote: >> >>> These patches improve qcow2 performance when used with cache=off. >>> >>> They modify block-qcow2.c to read/write as many clusters as >>> possible per bdrv_aio_[read|write](). >>> >>> >> This patch series looks like a pretty good clean up of the code. The >> perf improvement is a nice side effect too. >> >> I'm a little concerned about how much code this touches though. How >> > > Yes, I know, it's why I split it in several patches: easier to review, > easier to test. > > >> much testing have you done of these changes? Have you tested all of the >> corner cases (backing files, filling up a disk image, etc.)? >> > > Well, before all I made a lot of review of my modifications, but it must > also be reviewed by other eyes. > > I think it covers a lot of cases, but I didn't test encrypted disk image > and compressed disk image. The case with backed files was tested only > with mkfs/fsck/dbench. > > If you think these patches are good candidates to be included, I can > make more tests. > Yes, I do think these patches make sense. I would like to see more testing though. It all seemed pretty clear to me (breaking out the patches was very helpful!) but I am very worried about corrupting qcow2 images. Regards, Anthony Liguori > Regards, > Laurent >