On 2020-12-08 13:52:25 [+0100], To Daniel Wagner wrote: > On 2020-12-08 13:41:48 [+0100], Daniel Wagner wrote: > > On Tue, Dec 08, 2020 at 12:49:36PM +0100, Sebastian Andrzej Siewior wrote: > > > On 2020-12-08 12:36:53 [+0100], Daniel Wagner wrote: > > > > Obvious in this configuration there are no remote completions (verified > > > > it). > > > > > > do you complete on a remote CPU if you limit the queues to one (this is > > > untested of course)? > > > > nvme0n1/ completed 11913011 remote 6718563 56.40% > > > > yes, but how is this relevant? I thought Jens complain was about the > > additional indirection via the softirq context > > > > - rq->q->mq_ops->complete(rq); > > + blk_mq_trigger_softirq(rq); > > > > and not the remote completion path. I can benchmark it out but I don't > > know if it's really helping in the discussion. … blurp Yes, you are right. Even cross-CPU completion for single-queue was already completing in softirq. So the only change is for multiqueue devices which you just demonstrated that it does not happen. Thank you! Sebastian
