Messages in this thread | | | Date | Fri, 19 Jul 2013 10:01:43 -0400 | From | Ric Wheeler <> | Subject | Re: [Ksummit-2013-discuss] [ATTEND] scsi-mq prototype discussion |
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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
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