Package Details: linux-ck 4.12.7-2

Git Clone URL: (read-only)
Package Base: linux-ck
Description: The Linux-ck kernel and modules with the ck2 patchset featuring MuQSS CPU scheduler v0.160
Upstream URL:
Licenses: GPL2
Provides: linux-ck=4.12.7
Submitter: graysky
Maintainer: graysky
Last Packager: graysky
Votes: 365
Popularity: 2.572111
First Submitted: 2011-07-22 14:51
Last Updated: 2017-08-15 18:47

Latest Comments

mrkline commented on 2017-08-15 21:38

@graysky: See!msg/bfq-iosched/j4QUK4IPOhw/CY1LmmhcAwAJ, as previously mentioned - apparently other kernel devs have removed compile-time scheduler defaults.

I've been able to "fix" it for now with a udev rule, slightly modified from what @vp1981 posted:

ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/scheduler}="bfq"

(The wildcard was causing several false positives and errors to show up in the system log while booting.)

graysky commented on 2017-08-15 21:20

@mrkline - Interesting... I get the same.

mrkline commented on 2017-08-15 20:20

Scratch that, 4.12.7-2 seems to have the same issue.

mrkline commented on 2017-08-15 18:40

Apparently ck-2 contains changes to make BFQ the default scheduler:

So we should be good to go as soon as @graysky bumps this.

vp1981 commented on 2017-08-15 12:32

@mrkline, you may ask post-factum to translate new on, see, but this is receipt from the news:

Планировщики ввода-вывода при использовании blk-mq нельзя указывать через командную строку ядра в загрузчике. Вместо этого используйте правило udev, например:

ACTION=="add|change", KERNEL=="sd[a-z]*", ATTR{queue/scheduler}="bfq"

Чтобы включить подсистему blk-mq, ядро нужно собрать с опцией CONFIG_SCSI_MQ_DEFAULT=y или передать параметр scsi_mod.use_blk_mq=1 из загрузчика.

(my translation)
... use udev rule, for example:

ACTION=="add|change", KERNEL=="sd[a-z]*", ATTR{queue/scheduler}="bfq"

In order to enable blk-mq subsystem the kernel has to be configured with option CONFIG_SCSI_MQ_DEFAULT=y or pass parameter scsi_mod.use_blk_mq=1 in boot loader.

P.S. Gee, I found the news on post-factum site:, see "v4.12-pf2 is out" (

mrkline commented on 2017-08-15 07:27

@graysky 4.12.7-1 boots and runs fine on several of my boxen.

The only curious tidbit is that even though BFQ is set as the default:
$ zcat /proc/config.gz | grep -i BFQ

The kernel is defaulting to mq-deadline:
$ cat /sys/block/sda/queue/scheduler
[mq-deadline] kyber bfq none

Is this what @kwe was discussing below?

What's the simplest way to switch all disks to BFQ on boot in the meantime?

artafinde commented on 2017-08-15 06:49

Building 4.12.7-1. Apart for the changes in config so you have to configure lots more than before we are missing the CPU optimizations. Update: Got a non-bootable kernel. Trying a second build, config seems better now as expected (I'll blame ccache which I disabled now). #2 Update: Non bootable again, stuck at "Triggering udevents"

pedrogabriel commented on 2017-08-15 02:03

4.12.7-1 works like a charm.

kwe commented on 2017-08-14 19:58

@graysky That config option will disappear in the future because the behavior will be enabled by default:

Apparently this is planned for 4.13:

linux/drivers/scsi$ git tag --contains 5c279bd9e40624f4ab6e688671026d6005b066fa

So, when it comes around, you might want to remove it again. :)

beest commented on 2017-08-14 19:25

4.12.7-1 boots, everything seems kosher so far.

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