Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760997AbZDGU2G (ORCPT ); Tue, 7 Apr 2009 16:28:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760822AbZDGU1m (ORCPT ); Tue, 7 Apr 2009 16:27:42 -0400 Received: from mail-fx0-f158.google.com ([209.85.220.158]:36502 "EHLO mail-fx0-f158.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760833AbZDGU1k (ORCPT ); Tue, 7 Apr 2009 16:27:40 -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=YS/94u1+O4Lbf4r1yo9JBMeaY2MExFKOZNWJgPWu0XyKFNy8uyb6PQ8oQMtqd61fm/ k/LFyU+ublp/iOVNykSMCoWWgmepIsH8gSRA9546htJ/3TS7KQHcCaz8BGKkfQG9sPLz axtk1srVBnq8c8hQ8XrbPaXEwHfjdKQh8ZWZ0= MIME-Version: 1.0 In-Reply-To: <49DA49AA.1060106@wpkg.org> References: <49D7AD54.4060408@vlnb.net> <49D7B122.50103@wpkg.org> <49D9D9A0.40106@wpkg.org> <49DA33EF.3020700@vlnb.net> <49DA49AA.1060106@wpkg.org> Date: Tue, 7 Apr 2009 22:27:36 +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: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1762 Lines: 45 On Mon, Apr 6, 2009 at 8:27 PM, Tomasz Chmielewski wrote: > Note that crypt performance for SCST was worse than that of STGT for large > read-ahead values. > Also, SCST performance on crypt device was more or less the same with 256 > and 16384 readahead values. I wonder why performance didn't increase here > while increasing readahead values? Could anyone recheck if it's the same on > some other system? I have repeated the test for the non-encrypted case. Setup details: * target: 2.6.29.1 kernel, 64-bit, Intel E8400 CPU @ 3 GHz, 4 GB RAM, two ST3250410AS disks, with /dev/md3 set up in RAID-1 with a stripe size of 32 KB, local reading speed of /dev/md3: 120 MB/s, I/O scheduler: CFQ. * initiator: 2.6.28.7 kernel, 64-bit, Intel E6750 CPU @ 2.66 GHz, 2 GB RAM. * network: 1 Gbit/s Ethernet, two systems connected back to back via a crossed cable. Each test was repeated four times. Before each test the target caches were dropped via the command "sync; echo 3 > /proc/sys/vm/drop_caches". The following test has been run on the initiator: sync; echo 3 > /proc/sys/vm/drop_caches; dd if=/dev/sdb of=/dev/null bs=64K count=100000 Results with read-ahead set to 256 on the initiator, in MB/s: STGT 56.7 +/- 0.3 SCST 56.9 +/- 1.1 Results with read-ahead set to 16384 on the initiator, in MB/s: STGT 59.9 +/- 0.1 SCST 59.5 +/- 0.0 Or: slightly better results with the larger read-ahead value, and a performance difference well below 1% between the STGT and SCST performance results. 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/