On Tue, Jul 16, 2013 at 02:07:29PM -0700, 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. I'd be very interested in attending this, if invited. -- steve -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
