On Tue, Jan 30, 2018 at 11:08:28AM +0100, Johannes Thumshirn wrote: > [+Cc Mel] > Jens Axboe <axboe@xxxxxxxxx> writes: > > On 1/29/18 1:56 PM, James Bottomley wrote: > >> On Mon, 2018-01-29 at 23:46 +0800, Ming Lei wrote: > >> [...] > >>> 2. When to enable SCSI_MQ at default again? > >> > >> I'm not sure there's much to discuss ... I think the basic answer is as > >> soon as Christoph wants to try it again. > > > > FWIW, internally I've been running various IO intensive workloads on > > what is essentially 4.12 upstream with scsi-mq the default (with > > mq-deadline as the scheduler) and comparing IO workloads with a > > previous 4.6 kernel (without scsi-mq), and things are looking > > great. > > > > We're never going to iron out the last kinks with it being off > > by default, I think we should attempt to flip the switch again > > for 4.16. > > The 4.12 sounds interesting. I remember Mel ran some test with 4.12 as > we where considering to flip the config option for SLES and it showed > several road blocks. > Mostly due to slow storage and BFQ where mq-deadline was not a universal win as an alternative default. I don't have current data and I archived what I had, but it was based on 4.13-rc7 at the time and BFQ has changed a lot since so it would need to be redone. > I'm not sure whether he re-evaluated 4.13/4.14 on his grid though. > No, it hasn't. Grid time for performance testing has been tight during the last few months to say the least. > But I'm definitively interested in this discussion and can even possibly > share some benchmark results we did in our FC Lab. > If you remind me, I may be able to re-execute the tests in a 4.16-rcX before LSF/MM so you have other data to work with. Unfortunately, I'll not be able to make LSF/MM this time due to personal commitments that conflict and are unmovable. -- Mel Gorman SUSE Labs
