From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Garry Subject: Re: scsi-mq performance check Date: Fri, 18 Dec 2015 16:50:46 +0000 Message-ID: <56743966.5010309@huawei.com> References: <56741F04.3070506@huawei.com> <56742168.6030200@suse.de> <56742403.7000108@sandisk.com> <567427E8.8010608@huawei.com> <56742EC2.2020606@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from szxga03-in.huawei.com ([119.145.14.66]:15829 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932264AbbLRQ4S (ORCPT ); Fri, 18 Dec 2015 11:56:18 -0500 In-Reply-To: <56742EC2.2020606@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hannes Reinecke , Bart Van Assche , hch@infradead.org, "linux-scsi@vger.kernel.org" Cc: "zhangfei.gao@linaro.org" >> We have to lock due to how we reserve a slot in the delivery queue. >> We are looking to optimise this, but it's not straightforward. >> >> Perf is a good strategy, but, to be honest, I have not spent a lot >> of time looking at this so I'm looking for low hanging fruit initially. >> >> FYI, our hardware does have the same number of delivery and >> completion queues (32), and 16 cores. One thing to note is that a >> command which was sent on queue x is not quaranteed to complete on >> queue y. >> > ... then don't bother looking at scsi-mq. That is the very thing it > relies on ... > > Time to change the firmware? > > Cheers, > > Hannes Hi, Even though a slot delivered on queue x is not guaranteed to complete on completion queue x, is nearly always does (I just quickly tested on our new chip, and 100% of the time it is the same - I need to check with our hardware guys if this was only v1 of the IP). As for firmware, our controller does not have any. cheers,