Calculate Forum

Cl-Kernel Is Back

We missed it as much as you did. After seven months without cl-kernel, a Calculate Linux automatic kernel configuration tool forked from genkernel, we decided to resume its development. Better still, it was completely reshaped.

As it did not seem possible to launch make menuconfig in graphic mode on the Calculate 3 server, the new cl-kernel is written in Bash like its ancestor. Now it is included in calculate-toolkit, to be completed later by other utilities (hopefully developer fellows will join us for this project) and does not make a package of its own.

New features available

Contrary to what you might think, ¢l-kernel does not compile anything. It generates a kernel template, stored in /var/calculate/templates, which is responsible for modifying standard kernel options. To achieve this, it calls Calculate Utilities that, in their turn, edit the configuration file, as for any other package one would like to install or (re)configure (including calculate-sources).

Let us say that you wish to slightly modify the kernel to make it support a specific hardware. No problem: disable the ‘minimal’ USE flag for calculate-sources, to retrieve the source code (the CL kernel being provided in a binary package by default), then run cl-kernel. The custom configuration will be used for any subsequent update.

If the kernel takes too long to compile, you can speed up the procedure significantly by deselecting the many drivers and functions you will not need.

Use it with any kernel you like

cl-kernel can take any kernel found in the Portage tree. Considering that a random kernel would not have been preconfigured by CL, a standard configuration file will be generated in this case. Then a kernel configuration template will be created, that will only contain modifications of the default settings, thus reducing considerably its size.

With cl-kernel, using non-Calculate kernels is easy. There is no risk of kernel panic: your calculate-sources configuration can be applied to vanilla-sources or any other kernel flavour.


From now on, cl-kernel can read the current kernel configuration to find if initramfs is to be created. Detailed instructions will be published soon. To cut the long story short, all boot drivers must be included in the kernel if you do not want to use an initramfs. Your system will start quicker then.

Alexander Tratsevskiy reports having optimized his old laptop’s boot time from 11 to 6 seconds, simply by getting rid of initramfs and unnecessary modules.

Integration with your Calculate profile

This would probably be the moment for reading extensively on Calculate profiles and their parameters; more articles are coming on this topic. Feel free to create your own profile and test it (unless you have already done so). Just for information, we used cl-kernel to configure calculate-sources-3.19 you must have updated to.

To be continued…

© 2007-2020 Calculate Ltd.
Mastodon Mastodon