On Tue, Apr 27, 2021 at 08:52:53AM +0100, John Garry wrote: > On 27/04/2021 00:59, Ming Lei wrote: > > > Anyway, I'll look at adding code for a per-request queue sched tags to see > > > if it helps. But I would plan to continue to use a per hctx sched request > > > pool. > > Why not switch to per hctx sched request pool? > > I don't understand. The current code uses a per-hctx sched request pool, and > I said that I don't plan to change that. I forget why you didn't do that, because for hostwide tags, request is always 1:1 for either sched tags(real io sched) or driver tags(none). Maybe you want to keep request local to hctx, but never see related performance data for supporting the point, sbitmap queue allocator has been intelligent enough to allocate tag freed from native cpu. Then you just waste lots of memory, I remember that scsi request payload is a bit big. Thanks, Ming
