Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753958AbaGJNgZ (ORCPT ); Thu, 10 Jul 2014 09:36:25 -0400 Received: from kanga.kvack.org ([205.233.56.17]:52225 "EHLO kanga.kvack.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753406AbaGJNgK (ORCPT ); Thu, 10 Jul 2014 09:36:10 -0400 Date: Thu, 10 Jul 2014 09:36:09 -0400 From: Benjamin LaHaise To: Christoph Hellwig Cc: "Elliott, Robert (Server Storage)" , Jens Axboe , "dgilbert@interlog.com" , James Bottomley , Bart Van Assche , "linux-scsi@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: scsi-mq V2 Message-ID: <20140710133609.GO12478@kvack.org> References: <1403715121-1201-1-git-send-email-hch@lst.de> <20140708144829.GA5539@infradead.org> <53BD7041.5010300@interlog.com> <53BD9A24.7010203@kernel.dk> <94D0CD8314A33A4D9D801C0FE68B402958B9628B@G9W0745.americas.hpqcorp.net> <20140710062040.GB20146@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140710062040.GB20146@infradead.org> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 09, 2014 at 11:20:40PM -0700, Christoph Hellwig wrote: > On Thu, Jul 10, 2014 at 12:53:36AM +0000, Elliott, Robert (Server Storage) wrote: > > the problem still occurs - fio results in low or 0 IOPS, with perf top > > reporting unusual amounts of time spent in do_io_submit and io_submit. > > The diff between the two version doesn't show too much other possible > interesting commits, the most interesting being some minor block > updates. > > I guess we'll have to a manual bisect, I've pushed out a > scsi-mq.3-bisect-1 branch that is rebased to just before the merge of > the block tree, and a scsi-mq.3-bisect-2 branch that is just after > the merge of the block tree to get started. There is one possible concern that could be exacerbated by other changes in the system: if the application is running close to the bare minimum number of requests allocated in io_setup(), the per cpu reference counters will have a hard time batching things. It might be worth testing with an increased number of requests being allocated if this is the case. -ben -- "Thought is the essence of where you are now." -- 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/