On Tue, Apr 06, 2021 at 11:25:08PM +0100, John Garry wrote: > On 06/04/2021 04:19, Ming Lei wrote: > > Hi Ming, > > > Yanhui found that write performance is degraded a lot after applying > > hctx shared tagset on one test machine with megaraid_sas. And turns out > > it is caused by none scheduler which becomes default elevator caused by > > hctx shared tagset patchset. > > > > Given more scsi HBAs will apply hctx shared tagset, and the similar > > performance exists for them too. > > > > So keep previous behavior by still using default mq-deadline for queues > > which apply hctx shared tagset, just like before. > > I think that there a some SCSI HBAs which have nr_hw_queues > 1 and don't > use shared sbitmap - do you think that they want want this as well (without > knowing it)? I don't know but none has been used for them since the beginning, so not an regression of shared tagset, but this one is really. Thanks, Ming
