On Wed, Dec 12, 2018 at 2:07 PM Jeff Moyer jmoyer@redhat.com wrote:

Hi,

Chris Murphy lists@colorremedies.com writes:

...

I used two boot params: scsi_mod.use_blk_mq=1 elevator=bfq. I don't think that's a good way for a distribution to set the default though.

You shouldn't need the "scsi_mod.use_blk_mq=1" option. As of 4.19, scsi_mq is the default, and by 4.21 the legacy path will be gone. The right way for the distro to set the default I/O scheduler is to use udev rules.

Like I mentioned earlier in the thread, Fedora kernels does not set scsi_mq as the default. I don't know why.

# CONFIG_SCSI_MQ_DEFAULT is not set