switch to i/o-scheduler none

/etc/udev/rules.d# vi 60-ioschedulers.rules

# set scheduler for NVMe
ACTION=="add|change", KERNEL=="nvme[0-9]n[0-9]", ATTR{queue/scheduler}="none"
# # set scheduler for SSD and eMMC
ACTION=="add|change", KERNEL=="sd[a-z]*|mmcblk[0-9]*", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="none"
# # set scheduler for rotating disks
ACTION=="add|change", KERNEL=="sd[a-z]*", ATTR{queue/rotational}=="1", ATTR{queue/scheduler}="none"

to manually force either reboot or

udevadm trigger

Reason: under Hyper-V the Host OS re-schedules, so pre-scheduling is waste of time