On Wed, Dec 12, 2018 at 11:08 AM stan <stanl-fedorauser(a)vfemail.net> wrote:
On Tue, 11 Dec 2018 11:48:29 -0000
"Alan Jenkins" <alan.christopher.jenkins(a)gmail.com> wrote:
>  BFQ:
>  "I'd prefer if the distros would lead the way on this, as theyare
> the ones that will most likely see the most bug reports" - Jens
> Axboe, https://www.spinics.net/lists/linux-block/msg31062.html
I compiled a custom kernel from the fedora src.rpm for 4.19.8. I turned
off all schedulers except NOOP and BFQ. But there was no way in the
configuration process (make menuconfig) to set BFQ as default. I tried
setting it in kernel-local, but the build process errored because it
said NOOP is the default and that disagreed with my choice. I'm
running the kernel and it is using noop. And there is no way to change
it in the /sys hierarchy.
So, how do I get a fedora kernel to run BFQ?
Yep, so far in 4.20 there is neither a CONFIG_DEFAULT_BFQ or
CONFIG_DEFAULT_IOSCHED="bfq" near as I can tell. Maybe it's different
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.
I set the following in /etc/default/grub and then ran grub2-mkconfig
(not on Rawhide!)
GRUB_CMDLINE_LINUX="scsi_mod.use_blk_mq=1 elevator=bfq zswap.enabled=1
I also created /etc/dracut.conf.d/bfq.conf containing:
add_drivers+=" bfq "
yes, with spaces, and rebuilt the initramfs
But upon reboot, total implosion. Piles of USB errors and disconnects
(the boot device is a Samsung FIT USB stick which fits flush in an
Intel NUC). I didn't have time to troubleshoot what's causing this
problem, other than to plug the USB stick into another computer to
verify the stick is good and hasn't been corrupted. It's possibly
related the mq-blk bug in 4.19.0 through 4.19.7 - so I've since
upgraded to 4.19.8 which as those patches, but I haven't had a chance