On Tue, Sep 19, 2017 at 12:25:15PM -0700, Omar Sandoval wrote: > On Sat, Sep 02, 2017 at 11:17:15PM +0800, Ming Lei wrote: > > Hi, > > > > In Red Hat internal storage test wrt. blk-mq scheduler, we > > found that I/O performance is much bad with mq-deadline, especially > > about sequential I/O on some multi-queue SCSI devcies(lpfc, qla2xxx, > > SRP...) > > > > Turns out one big issue causes the performance regression: requests > > are still dequeued from sw queue/scheduler queue even when ldd's > > queue is busy, so I/O merge becomes quite difficult to make, then > > sequential IO degrades a lot. > > > > The 1st five patches improve this situation, and brings back > > some performance loss. > > Sorry it took so long, I've reviewed or commented on patches 1-6. When > you send v5, could you just send patches 1-6, and split the rest as > their own series? Sure, no problem. Thanks for your review! -- Ming
