On 3/10/22 5:36 PM, Jens Axboe wrote: > I'm assuming you have a plug setup for doing the reads, which is why you > see the big difference (or there would be none). But > blk_mq_flush_plug_list() should really take care of this when the plug > is flushed, requests should be merged at that point. And from your > description, doesn't sound like they are at all. Maybe you need a list sort in blk_mq_flush_plug_list(). If you round-robin all the drives, then we'll hit that "run queue" path for each of them when we flush. -- Jens Axboe
