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* Why BFQ scheduler available only for NVMe device?
@ 2018-10-04 16:15 Mikhail Gavrilov
  2018-10-04 16:26 ` Jens Axboe
  0 siblings, 1 reply; 2+ messages in thread
From: Mikhail Gavrilov @ 2018-10-04 16:15 UTC (permalink / raw)
  To: linux-block

Sorry I don't finded answer on my question.
Why BFQ scheduler available only for NVMe device?

$ find /sys -name scheduler -exec grep . {} +
find: =E2=80=98/sys/kernel/debug=E2=80=99: Permission denied
find: =E2=80=98/sys/fs/pstore=E2=80=99: Permission denied
find: =E2=80=98/sys/fs/bpf=E2=80=99: Permission denied
/sys/devices/pci0000:00/0000:00:01.3/0000:02:00.1/ata5/host4/target4:0:0/4:=
0:0:0/block/sda/queue/scheduler:noop
deadline [cfq]
/sys/devices/pci0000:00/0000:00:01.1/0000:01:00.0/nvme/nvme0/nvme0n1/queue/=
scheduler:[none]
mq-deadline bfq
/sys/devices/pci0000:00/0000:00:07.1/0000:0c:00.3/usb4/4-3/4-3.4/4-3.4.1/4-=
3.4.1:1.0/host9/target9:0:0/9:0:0:0/block/sdb/queue/scheduler:noop
deadline [cfq]

$ uname -r
4.19.0-0.rc5.git3.1.fc30.x86_64

$ cat /boot/config-`uname -r` | grep -i bfq
CONFIG_IOSCHED_BFQ=3Dm
CONFIG_BFQ_GROUP_IOSCHED=3Dy


--
Best Regards,
Mike Gavrilov.

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: Why BFQ scheduler available only for NVMe device?
  2018-10-04 16:15 Why BFQ scheduler available only for NVMe device? Mikhail Gavrilov
@ 2018-10-04 16:26 ` Jens Axboe
  0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2018-10-04 16:26 UTC (permalink / raw)
  To: Mikhail Gavrilov, linux-block

On 10/4/18 10:15 AM, Mikhail Gavrilov wrote:
> Sorry I don't finded answer on my question.
> Why BFQ scheduler available only for NVMe device?
> 
> $ find /sys -name scheduler -exec grep . {} +
> find: ‘/sys/kernel/debug’: Permission denied
> find: ‘/sys/fs/pstore’: Permission denied
> find: ‘/sys/fs/bpf’: Permission denied
> /sys/devices/pci0000:00/0000:00:01.3/0000:02:00.1/ata5/host4/target4:0:0/4:0:0:0/block/sda/queue/scheduler:noop
> deadline [cfq]
> /sys/devices/pci0000:00/0000:00:01.1/0000:01:00.0/nvme/nvme0/nvme0n1/queue/scheduler:[none]
> mq-deadline bfq
> /sys/devices/pci0000:00/0000:00:07.1/0000:0c:00.3/usb4/4-3/4-3.4/4-3.4.1/4-3.4.1:1.0/host9/target9:0:0/9:0:0:0/block/sdb/queue/scheduler:noop
> deadline [cfq]

It isn't, but it's only available for MQ devices. For SCSI, you want to
set:

CONFIG_SCSI_MQ_DEFAULT=y                                                        

and if that isn't feasible due to running a distro build, then you want
to add scsi_mod.use_blk_mq=1 to your boot parameters.

-- 
Jens Axboe

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2018-10-04 23:09 UTC | newest]

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2018-10-04 16:15 Why BFQ scheduler available only for NVMe device? Mikhail Gavrilov
2018-10-04 16:26 ` Jens Axboe

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