On Tue, Oct 30, 2018 at 12:32:36PM -0600, Jens Axboe wrote: > This series adds support for multiple queue maps for blk-mq. > Since blk-mq was introduced, it's only support a single queue > map. This means you can have 1 set of queues, and the mapping > purely depends on what CPU an IO originated from. With this > patch set, drivers can implement mappings that depend on both > CPU and request type - and they can have multiple sets of mappings. > > NVMe is used as a proof of concept. It adds support for a separate > write queue set. One way to use this would be to limit the number > of write queues to favor reads, since NVMe does round-robin service > of queues. An easy extension of this would be to add multiple > sets of queues, for prioritized IO. > > NVMe also uses this feature to finally make the polling work > efficiently, without triggering interrupts. This both increases > performance (and decreases latency), at a lower system load. At > the same time it's more flexible, as you don't have to worry about > IRQ coalescing and redirection to avoid interrupts disturbing the > workload. This is how polling should have worked from day 1. > > This is on top of my mq-conversions branch. It can also be bound > in my mq-maps branch. Looks good to me. For the series: Reviewed-by: Keith Busch <keith.busch@xxxxxxxxx>
