On Thu, 13 Dec 2018 17:24:21 +0100
Tomasz Torcz <tomek(a)pipebreaker.pl> wrote:
On Wed, Dec 12, 2018 at 04:30:20PM -0700, stan wrote:
> Enabled deadline and cfq again, but still no bfq available.
> $ cat /sys/block/sda/queue/scheduler
> noop deadline [cfq]
Those are single-queue scheduler. Multiqueue uses different
schedulers: bfq, kyber, mq-deadline. MQ schedulers won't appear on
single-queue devices even if you modprobe such schedulers.
You probably need “scsi_mod.use_blk_mq=y dm_mod.use_blk_mq=y” kernel
commandline options, although I think those are default in recent
kernels.
Thanks. I got the impression from the documentation I read that BFQ
operated for both mq and single queue. In fact, IIRC it actually
degraded mq performance slightly, but enhanced single queue
performance. I guess I was wrong. I'll try the above to see if it
enables me to use bfq on single queue devices.