On Tue, Jun 05, 2018 at 03:57:05PM -0700, Roland Dreier wrote: > That makes sense but I'm not sure it covers everything. Probably the > most common way to do NVMe/RDMA will be with a single HCA that has > multiple ports, so there's no sensible CPU locality. On the other > hand we want to keep both ports to the fabric busy. Setting different > paths for different queues makes sense, but there may be > single-threaded applications that want a different policy. > > I'm not saying anything very profound, but we have to find the right > balance between too many and too few knobs.
Agreed. And the philosophy here is to start with a as few knobs as possible and work from there based on actual use cases. Single threaded applications will run into issues with general blk-mq philosophy, so to work around that we'll need to dig deeper and allow borrowing of other cpu queues if we want to cater for that.
