- 1 General package details
- 2 Installation options
- 3 How to enable the BFQ I/O Scheduler
- 4 More about MuQSS
- 5 Troubleshooting
- 5.1 Running VirtualBox with Linux-ck
- 5.2 Downgrading
- 5.3 Forum support
- 6 See also
General package details
AUR and in the unofficial repo-ck repository that allows users to run a kernel and headers setup patched with Con Kolivas' ck patchset, including MuQSS (Multiple Queue Skiplist Scheduler, pronounced mux) which replaces Brain Fuck Scheduler (BFS), his previous work. Many Arch Linux users choose this kernel for its excellent desktop interactivity and responsiveness under any load situation.AUR is a package available both in
Ck patchset is designed for desktop/laptop use but not for servers. It provides low latency environment and works well for 16 CPUs or fewer.
Linux-ck roughly follows the release cycle of the official ARCH kernel but not only. The following are requirements for a new package release:
- CK patchset compatible with the current kernel version
- corresponding ARCH kernel must be in existence otherwise it will break other packages i.e. nvidia. See git.archlinux.org for the official package
There are three modifications to the config files:
- The options that the CK patchset enable/disable.
- The tickrate is set to 100 Hz (CK's recommendation).
- The extra CPU types optionally available to compilation thanks to the GCC patch.
All other options are set to the ARCH defaults outlined in the main kernel's config files. Of course users are free to edit them.
The below).AUR package contains an option to switch on the nconfig config editor (see the section
Long-Term Support (LTS) CK releases
In addition to theAUR package, there are LTS kernel releases patched with the above patchsets as well and with the previously mentioned modifications:
- AUR - The current Arch Linux LTS kernel patched with the CK patchset
Users have two options to get these kernel packages.
Compile the package from source
The AUR contains entries for both packages mentioned above.
Users can further customize the linux-ck package via tweaks contained in the PKGBUILD:
- Optional nconfig for user specific tweaking.
- Option to compile a minimal set of modules via a make localmodconfig.
- Option to bypass the standard ARCH config options and simply use the current kernel configuration file.
- Optionally set the BFQ I/O scheduler as default.
More details about these options are provided in the PKGBUILD itself. Be sure to read them carefully if compiling from AUR!
Use pre-compiled packages
How to enable the BFQ I/O Scheduler
Budget Fair Queueing is a disk scheduler which allows each process/thread to be assigned a portion of the disk throughput. Its creator shares the results of many benchmarks (results and video) which show the latency performance improvement.
Due to CK's patchset defaults, BFQ is built into linux-ck but the above-mentioned scheduler must be enabled manually. User has several options to do that.
Enable BFQ for all devices
If compiling from the AUR, simply set the BFQ flag to "y" in the PKGBUILD prior to building
Enable BFQ only for specific devices
An alternative method is to instruct the kernel at runtime to use BFQ on a device-by-device basis. For configuration examples see the Improving performance#Tuning IO schedulers section.
More about MuQSS
See the LKML announcement posted by CK.
Check if MuQSS is enabled
This start-up message should appear in the kernel ring buffer when MuQSS in enabled:
$ dmesg | grep -i muqss ... MuQSS CPU scheduler v0.120 by Con Kolivas.
MuQSS patched kernels and systemd
It is a common mistake to think that MuQSS does not support cgroups. It does but not all the cgroup features (e.g. CPU limiting will not work).
Running VirtualBox with Linux-ck
VirtualBox works just fine with custom kernels such as Linux-ck without the need to keep any of the official ARCH kernel headers package on the system.
Do not forget to add users to the vboxusers group:
# gpasswd -a USERNAME vboxusers
Use the unofficial repo (recommended if Linux-ck is installed from Repo-ck)
See the Repo-ck section to set up it correctly.
The virtualbox-ck-host-modules package (recommended if Linux-ck is built from AUR)
Install theAUR package and then install the virtualbox package.
Use DKMS (more complicated, recommended for LTS versions)
Install virtualbox with the virtualbox-host-dkms package. Then setup DKMS as follows:
# pacman -S virtualbox virtualbox-host-dkms # dkms install vboxhost/4.3.12
Users wishing to downgrade to a previous version of Linux-ck, have several options:
- Source archives are available dating back to linux-ck-3.3.7-1.
- AUR.git holds AUR git commits for Linux-ck, dating back to linux-ck-126.96.36.199-1.
Always feel free to open a thread in the forums for support purpose. Be sure to give the thread a descriptive title to draw attention to the fact that the post relates to the Linux-ck package.