Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757520AbZDFTCL (ORCPT ); Mon, 6 Apr 2009 15:02:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755223AbZDFTBw (ORCPT ); Mon, 6 Apr 2009 15:01:52 -0400 Received: from mail-fx0-f158.google.com ([209.85.220.158]:45306 "EHLO mail-fx0-f158.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753178AbZDFTBv convert rfc822-to-8bit (ORCPT ); Mon, 6 Apr 2009 15:01:51 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=gE4H3/+JWy5WZJFG6BeYXYmENDWgSZuCdKF6Uy1mw1X0sPriJ7KhztCk7ITtb/QT7C x27Dh/kr99kpKz/WsMuys8LJvfEftenma2a78ohWfi6+4PRUZyVUfYGKVBW66v6snNSY rvaAGduo+IqVgvfwoPXS0pzBDqXshDW2HQM8k= MIME-Version: 1.0 In-Reply-To: <49D9D9A0.40106@wpkg.org> References: <49D7AD54.4060408@vlnb.net> <49D7B122.50103@wpkg.org> <49D9D9A0.40106@wpkg.org> Date: Mon, 6 Apr 2009 21:01:47 +0200 Message-ID: Subject: Re: [Scst-devel] [ANNOUNCE]: Comparison of features sets between different SCSI targets (SCST, STGT, IET, LIO) From: Bart Van Assche To: Tomasz Chmielewski Cc: Vladislav Bolkhovitin , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, iscsitarget-devel@lists.sourceforge.net, James Bottomley , scst-devel , stgt@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2130 Lines: 63 On Mon, Apr 6, 2009 at 12:29 PM, Tomasz Chmielewski wrote: > The target is running Debian Lenny 64bit userspace on an Intel Celeron > 2.93GHz CPU, 2 GB RAM. > > Initiator is running Debian Etch 64 bit userspace, open-iscsi 2.0-869, Intel > Xeon 3050/2.13GHz, 8 GB RAM. > > > Each test was repeated 6 times, "sync" was made and caches were dropped on > both sides before each test was started. > > dd parameters were like below, so 6.6 GB of data was read each time: > > dd if=/dev/sdag of=/dev/null bs=64k count=100000 > > > Data was read from two block devices: > - /dev/md0, which is RAID-1 on two ST31500341AS 1.5 TB drives > - encrypted dm-crypt device which is on top of /dev/md0 > > Encrypted device was created with the following additional options passed to > cryptsetup > (it provides the most performance on systems where CPU is a bottleneck, but > with decreased > security when compared to default options): > > -c aes-ecb-plain -s 128 > > > Generally, CPU on the target was a bottleneck, so I also tested the load on > target. > > > md0, crypt columns - averages from dd > us, sy, id, wa - averages from vmstat > > > 1. Disk speeds on the target > > Raw performance: 102.17 MB/s > Raw performance (encrypted): ?50.21 MB/s > > > 2. Read-ahead on the initiator: 256 (default); md0, crypt - MB/s > > ? ? ? ? ? ? ? ? ? ? ? ? ?md0 ? us ?sy ?id ?wa ?| crypt ? us ?sy ?id ?wa > ?STGT ? ? ? ? ? ? ? ? ? ? ?50.63 ? 4% 45% 18% 33% | 32.52 ? ?3% 62% 16% 19% > SCST (debug + no patches) 43.75 ? 0% 26% 30% 44% | 42.05 ? ?0% 84% ?1% 15% > SCST (fullperf + patches) 45.18 ? 0% 25% 33% 42% | 44.12 ? ?0% 81% ?2% 17% Hello Tomasz, How is it possible that for this test the read performance through STGT (50.63 MB/s) was higher than the read performance on the target (50.21 MB/s) ? Are you sure that all read buffers were flushed before this test was started ? Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/