Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760160Ab3GSOCh (ORCPT ); Fri, 19 Jul 2013 10:02:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:28114 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751941Ab3GSOCd (ORCPT ); Fri, 19 Jul 2013 10:02:33 -0400 Message-ID: <51E946C7.3020502@redhat.com> Date: Fri, 19 Jul 2013 10:01:43 -0400 From: Ric Wheeler User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: James Bottomley CC: Jens Axboe , "ksummit-2013-discuss@lists.linuxfoundation.org" , James Smart , linux-scsi , LKML , "scameron@beardog.cce.hp.com" , "kmo@daterainc.com" , target-devel , Hannes Reinecke , Tejun Heo , Christoph Hellwig , Andrew Vasquez Subject: Re: [Ksummit-2013-discuss] [ATTEND] scsi-mq prototype discussion 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> <20130716211529.GQ22392@kernel.dk> <1374036751.2045.20.camel@dabdike> In-Reply-To: <1374036751.2045.20.camel@dabdike> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4660 Lines: 97 On 07/17/2013 12:52 AM, James Bottomley wrote: > On Tue, 2013-07-16 at 15:15 -0600, Jens Axboe wrote: >> 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. > Heh well, given that most of the block mq discussions at LSF have been > you saying you really should get around to cleaning up and posting the > code, you'll understand my wanting to see that happen first ... > > I suppose we could try to run a storage workshop within KS, but I think > most of the mini summit slots have already gone. There's also plumbers > if all slots are gone (I would say that, being biased and on the > programme committee) Ric is running the storage and Filesystems MC > > http://www.linuxplumbersconf.org/2013/ocw/events/LPC2013/tracks/159 > > James > And we still are looking for suggested topics - it would be great to have the multi-queue work at plumbers. You can post a proposal for it (or other topics) here: http://www.linuxplumbersconf.org/2013/ocw/events/LPC2013/proposals Ric -- 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/