[{"id":1769619,"web_url":"http://patchwork.ozlabs.org/comment/1769619/","msgid":"","list_archive_url":null,"date":"2017-09-16T16:25:19","subject":"Re: [Qemu-devel] [PATCH v3 1/7] block: use 1 MB bounce buffers for\n\tcrypto instead of 16KB","submitter":{"id":36836,"url":"http://patchwork.ozlabs.org/api/people/36836/","name":"Max Reitz","email":"mreitz@redhat.com"},"content":"On 2017-09-12 13:28, Daniel P. Berrange wrote:\n> Using 16KB bounce buffers creates a significant performance\n> penalty for I/O to encrypted volumes on storage which high\n> I/O latency (rotating rust & network drives), because it\n> triggers lots of fairly small I/O operations.\n> \n> On tests with rotating rust, and cache=none|directsync,\n> write speed increased from 2MiB/s to 32MiB/s, on a par\n> with that achieved by the in-kernel luks driver. With\n> other cache modes the in-kernel driver is still notably\n> faster because it is able to report completion of the\n> I/O request before any encryption is done, while the\n> in-QEMU driver must encrypt the data before completion.\n> \n> Reviewed-by: Eric Blake \n> Reviewed-by: Stefan Hajnoczi \n> Signed-off-by: Daniel P. Berrange \n> ---\n> block/crypto.c | 12 +++++-------\n> 1 file changed, 5 insertions(+), 7 deletions(-)\n\nReviewed-by: Max Reitz ","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=)","ext-mx01.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com","ext-mx01.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=mreitz@redhat.com"],"Received":["from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xvd1r5xdYz9s7c\n\tfor ;\n\tSun, 17 Sep 2017 02:26:24 +1000 (AEST)","from localhost ([::1]:57922 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t)\n\tid 1dtFvC-0003Fc-T7\n\tfor incoming@patchwork.ozlabs.org; Sat, 16 Sep 2017 12:26:22 -0400","from eggs.gnu.org ([2001:4830:134:3::10]:48007)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dtFuL-0003AY-Oh\n\tfor qemu-devel@nongnu.org; Sat, 16 Sep 2017 12:25:30 -0400","from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from ) id 1dtFuK-00066N-Tk\n\tfor qemu-devel@nongnu.org; Sat, 16 Sep 2017 12:25:29 -0400","from mx1.redhat.com ([209.132.183.28]:37700)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from )\n\tid 1dtFuF-00062y-Ly; Sat, 16 Sep 2017 12:25:23 -0400","from smtp.corp.redhat.com\n\t(int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id C7E5E81DEA;\n\tSat, 16 Sep 2017 16:25:22 +0000 (UTC)","from dresden.str.redhat.com (ovpn-204-52.brq.redhat.com\n\t[10.40.204.52])\n\tby smtp.corp.redhat.com (Postfix) with ESMTPS id 3AD4E60468;\n\tSat, 16 Sep 2017 16:25:21 +0000 (UTC)"],"DMARC-Filter":"OpenDMARC Filter v1.3.2 mx1.redhat.com C7E5E81DEA","To":"\"Daniel P. Berrange\" , qemu-devel@nongnu.org","References":"<20170912112855.24269-1-berrange@redhat.com>\n\t<20170912112855.24269-2-berrange@redhat.com>","From":"Max Reitz ","Message-ID":"","Date":"Sat, 16 Sep 2017 18:25:19 +0200","User-Agent":"Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101\n\tThunderbird/52.3.0","MIME-Version":"1.0","In-Reply-To":"<20170912112855.24269-2-berrange@redhat.com>","Content-Type":"multipart/signed; micalg=pgp-sha256;\n\tprotocol=\"application/pgp-signature\";\n\tboundary=\"frj6fnd4rdbfNpXe5ksRIINTJWj3G7EHS\"","X-Scanned-By":"MIMEDefang 2.79 on 10.5.11.11","X-Greylist":"Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.25]);\n\tSat, 16 Sep 2017 16:25:22 +0000 (UTC)","X-detected-operating-system":"by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]\n\t[fuzzy]","X-Received-From":"209.132.183.28","X-Content-Filtered-By":"Mailman/MimeDel 2.1.21","Subject":"Re: [Qemu-devel] [PATCH v3 1/7] block: use 1 MB bounce buffers for\n\tcrypto instead of 16KB","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.21","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"Kevin Wolf , Stefan Hajnoczi ,\n\tqemu-block@nongnu.org","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"\"Qemu-devel\"\n\t"}}]