From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH 00/10] mpt3sas: full mq support Date: Tue, 31 Jan 2017 12:16:52 +0100 Message-ID: <9a9d5acd-5f51-ad5b-7364-1d7549c040fd@suse.de> References: <1485854760-122683-1-git-send-email-hare@suse.de> <20170131100243.GA1811@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:36193 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750750AbdAaLRN (ORCPT ); Tue, 31 Jan 2017 06:17:13 -0500 In-Reply-To: <20170131100243.GA1811@lst.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Christoph Hellwig Cc: "Martin K. Petersen" , James Bottomley , linux-scsi@vger.kernel.org, Sathya Prakash , Kashyap Desai , mpt-fusionlinux.pdl@broadcom.com On 01/31/2017 11:02 AM, Christoph Hellwig wrote: > On Tue, Jan 31, 2017 at 10:25:50AM +0100, Hannes Reinecke wrote: >> Hi all, >> >> this is a patchset to enable full multiqueue support for the mpt3sas driver. >> While the HBA only has a single mailbox register for submitting commands, >> it does have individual receive queues per MSI-X interrupt and as such >> does benefit from converting it to full multiqueue support. > > Explanation and numbers on why this would be beneficial, please. > We should not need multiple submissions queues for a single register > to benefit from multiple completion queues. > Well, the actual throughput very strongly depends on the blk-mq-sched patches from Jens. As this is barely finished I didn't post any numbers yet. However: With multiqueue support: 4k seq read : io=60573MB, bw=1009.2MB/s, iops=258353, runt= 60021msec With scsi-mq on 1 queue: 4k seq read : io=17369MB, bw=296291KB/s, iops=74072, runt= 60028msec So yes, there _is_ a benefit. (Which is actually quite cool, as these tests were done on a SAS3 HBA, so we're getting close to the theoretical maximum of 1.2GB/s). (Unlike the single-queue case :-) Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking hare@suse.de +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg)