From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: SCSI mid layer and high IOPS capable devices Date: Tue, 11 Dec 2012 09:21:46 +0100 Message-ID: <50C6ED1A.7040404@acm.org> References: <20121211000013.GI23107@beardog.cce.hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from juliette.telenet-ops.be ([195.130.137.74]:44537 "EHLO juliette.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752934Ab2LKIVu (ORCPT ); Tue, 11 Dec 2012 03:21:50 -0500 In-Reply-To: <20121211000013.GI23107@beardog.cce.hp.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: scameron@beardog.cce.hp.com Cc: linux-scsi@vger.kernel.org, stephenmcameron@gmail.com, dab@hp.com On 12/11/12 01:00, scameron@beardog.cce.hp.com wrote: > I tried using scsi_debug with fake_rw and also the scsi_ram driver > that was recently posted to get some idea of what the maximum IOPS > that could be pushed through the SCSI midlayer might be, and the > numbers were a little disappointing (was getting around 150k iops > with scsi_debug with reads and writes faked, and around 3x that > with the block driver actually doing the i/o). With which request size was that ? I see about 330K IOPS @ 4 KB and about 540K IOPS @ 512 bytes with the SRP protocol, a RAM disk at the target side, a single SCSI LUN and a single IB cable. These results have been obtained on a setup with low-end CPU's. Had you set rq_affinity to 2 in your tests ? Bart.