From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47905) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y1DoO-0005sm-Gq for qemu-devel@nongnu.org; Wed, 17 Dec 2014 07:34:49 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y1DoF-0005U4-Ds for qemu-devel@nongnu.org; Wed, 17 Dec 2014 07:34:40 -0500 Received: from mail-wi0-x232.google.com ([2a00:1450:400c:c05::232]:43017) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y1DoF-0005Ts-6P for qemu-devel@nongnu.org; Wed, 17 Dec 2014 07:34:31 -0500 Received: by mail-wi0-f178.google.com with SMTP id em10so15814412wid.17 for ; Wed, 17 Dec 2014 04:34:30 -0800 (PST) Sender: Paolo Bonzini Message-ID: <54917852.2060201@redhat.com> Date: Wed, 17 Dec 2014 13:34:26 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1418305950-30924-1-git-send-email-pbonzini@redhat.com> <1418305950-30924-2-git-send-email-pbonzini@redhat.com> <20141216110727.GA27195@noname.str.redhat.com> <54901764.6050307@redhat.com> <20141216131034.GA3301@noname.str.redhat.com> <549079CC.4010109@redhat.com> <5490958E.8030803@redhat.com> In-Reply-To: <5490958E.8030803@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 1/5] linux-aio: queue requests that cannot be submitted List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: ming.lei@canonical.com, pl@kamp.de, qemu-devel@nongnu.org, stefanha@redhat.com On 16/12/2014 21:26, Paolo Bonzini wrote: > >> I could reproduce this very well on a random OS image that I had around. >> This is raw over XFS over dm-crypt, and the image is about 75% sparse >> (8.2G used over 35G). I only get 1-2%, but still it's visible. >> >> However I can hardly reproduce it when using a partition directly: >> >> old new >> mean 9.9565 9.9636 (+0.07%) >> stddev 0.0405 0.0537 >> min 9.871 9.867 >> median 9.973 9.971 >> max 10.01 10.053 >> count 20 20 >> >> I haven't tried removing layers (e.g. fully-allocated XFS image without >> dm-crypt). > > Could not reproduce it with a fully-allocated XFS image, on the contrary > the patched QEMU is a bit faster: > > old new > mean 14.83325 14.82660 > stddev 0.016930 0.010328 > min 14.819 14.818 > max 14.854 14.883 > median 14.8225 14.8255 > count 20 20 Same for 50% sparse XFS image, patched QEMU a bit faster: old new Mean 8.31285 8.30625 stddev 0.03690 0.03333 min 8.277 8.276 max 8.378 8.382 median 8.292 8.2905 count 20 20