Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934089Ab3GPVQH (ORCPT ); Tue, 16 Jul 2013 17:16:07 -0400 Received: from merlin.infradead.org ([205.233.59.134]:48502 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933954Ab3GPVPt (ORCPT ); Tue, 16 Jul 2013 17:15:49 -0400 Date: Tue, 16 Jul 2013 15:15:29 -0600 From: Jens Axboe To: "Nicholas A. Bellinger" Cc: James Bottomley , Hannes Reinecke , "ksummit-2013-discuss@lists.linuxfoundation.org" , James Smart , linux-scsi , LKML , "kmo@daterainc.com" , target-devel , Andrew Vasquez , Tejun Heo , Christoph Hellwig , "scameron@beardog.cce.hp.com" Subject: Re: [Ksummit-2013-discuss] [ATTEND] scsi-mq prototype discussion Message-ID: <20130716211529.GQ22392@kernel.dk> References: <1373588612.7397.447.camel@haakon3.risingtidesystems.com> <20130712010223.GA15673@kroah.com> <1373592815.7397.477.camel@haakon3.risingtidesystems.com> <51DFDFF5.80702@suse.de> <1373698410.2922.10.camel@dabdike> <1374008849.7397.853.camel@haakon3.risingtidesystems.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1374008849.7397.853.camel@haakon3.risingtidesystems.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3752 Lines: 81 On Tue, Jul 16 2013, Nicholas A. Bellinger wrote: > On Sat, 2013-07-13 at 06:53 +0000, James Bottomley wrote: > > On Fri, 2013-07-12 at 12:52 +0200, Hannes Reinecke wrote: > > > On 07/12/2013 03:33 AM, Nicholas A. Bellinger wrote: > > > > On Thu, 2013-07-11 at 18:02 -0700, Greg KH wrote: > > > >> On Thu, Jul 11, 2013 at 05:23:32PM -0700, Nicholas A. Bellinger wrote: > > > >>> Drilling down the work items ahead of a real mainline push is high on > > > >>> priority list for discussion. > > > >>> > > > >>> The parties to be included in such a discussion are: > > > >>> > > > >>> - Jens Axboe (blk-mq author) > > > >>> - James Bottomley (scsi maintainer) > > > >>> - Christoph Hellwig (scsi) > > > >>> - Martin Petersen (scsi) > > > >>> - Tejun Heo (block + libata) > > > >>> - Hannes Reinecke (scsi error recovery) > > > >>> - Kent Overstreet (block, per-cpu ida) > > > >>> - Stephen Cameron (scsi-over-pcie driver) > > > >>> - Andrew Vasquez (qla2xxx LLD) > > > >>> - James Smart (lpfc LLD) > > > >> > > > >> Isn't this something that should have been discussed at the storage > > > >> mini-summit a few months ago? > > > > > > > > The scsi-mq prototype, along with blk-mq (in it's current form) did not > > > > exist a few short months ago. ;) > > > > > > > >> It seems very specific to one subsystem to be a kernel summit topic, > > > >> don't you think? > > > > > > > > It's no more subsystem specific than half of the other proposals so far, > > > > and given it's reach across multiple subsystems (block, scsi, target), > > > > and the amount of off-list interest on the topic, I think it would make > > > > a good candidate for discussion. > > > > > > > And it'll open up new approaches which previously were dismissed, > > > like re-implementing multipathing on top of scsi-mq, giving us the > > > single scsi device like other UNIX systems. > > > > > > Also I do think there's quite some synergy to be had, as with blk-mq > > > we could nail each queue to a processor, which would eliminate the > > > need for locking. > > > Which could be useful for other subsystems, too. > > > > Lets start with discussing this on the list, please, and then see where > > we go from there ... > > > > Yes, the discussion is beginning to make it's way to the list. I've > mostly been waiting for blk-mq to get a wider review before taking the > early scsi-mq prototype driver to a larger public audience. > > Primarily, I'm now reaching out to the people most effected by existing > scsi_request_fn() based performance limitations. Most of them have > abandoned existing scsi_request_fn() based logic in favor of raw block > make_request() based drivers, and are now estimating the amount of > effort to move to an scsi-mq based approach. > > Regardless, as the prototype progresses over the next months, having a > face-to-face discussion with the key parties in the room would be very > helpful given the large amount of effort involved to actually make this > type of generational shift in SCSI actually happen. There's a certain amount of overlap with the aio/O_DIRECT work as well. But if it's not a general session, could always be a BOF or something. I'll second the argument that most technical topics probably DO belong in a topic related workshop. But that leaves us with basically only process related topics at KS, I don't think it hurts to have a bit of tech meat on the bone too. At least I personally miss that part of KS from years gone by. -- Jens Axboe -- 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/