> Il giorno 12 dic 2018, alle ore 20:30, Chris Murphy <lists@xxxxxxxxxxxxxxxxx> ha scritto: > > Really Readding devel@ this time... > > On Wed, Dec 12, 2018 at 11:08 AM stan <stanl-fedorauser@xxxxxxxxxxx> wrote: >> >> On Tue, 11 Dec 2018 11:48:29 -0000 >> "Alan Jenkins" <alan.christopher.jenkins@xxxxxxxxx> wrote: >> >>> [3] BFQ: >>> http://algo.ing.unimo.it/people/paolo/disk_sched/description.php >>> >>> [4] >>> https://unix.stackexchange.com/questions/375600/how-to-enable-and-use-the-bfq-scheduler >>> >>> [5] "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? > > Short version: > 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 > for 4.21. > Yep, hundreds of kilobytes of email have been spent trying to convince Jens Axboe that a default option had to be kept for blk-mq too. At no avail. If anyone wants to restart this fight, I'll be on your side. > I used two boot params: scsi_mod.use_blk_mq=1 Yes, this is needed to switch to blk-mq, until 4.21, when there will be no legacy block any longer. One can also set the corresponding option in the kernel configuration. > elevator=bfq. I'm not sure this option works with blkmq. IIRC doing this may even cause system failures with blk-mq (but maybe this has been fixed). AFAIK, the only way is to set bfq manually or through, e.g., dev rules, but YMMV. > I don't > think that's a good way for a distribution to set the default though. > > Icky version: > > 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 > zswap.max_pool_percent=25 zswap.compressor=lz4" > > 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 > to retest. > I doubt this is bfq fault, as bfq is rather frequently used for USB too. Probably bfq has not been activated at all. Paolo > -- > Chris Murphy > _______________________________________________ > kernel mailing list -- kernel@xxxxxxxxxxxxxxxxxxxxxxx > To unsubscribe send an email to kernel-leave@xxxxxxxxxxxxxxxxxxxxxxx > Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines > List Archives: https://lists.fedoraproject.org/archives/list/kernel@xxxxxxxxxxxxxxxxxxxxxxx _______________________________________________ kernel mailing list -- kernel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to kernel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/kernel@xxxxxxxxxxxxxxxxxxxxxxx
