Showing posts with label kernel. Show all posts
Showing posts with label kernel. Show all posts

Thursday, November 13, 2014

Isolating CPUs from the general scheduler in Linux.

It could be done using the kernel parameters:

isolcpus=

Format:

<cpu number>,...,<cpu number>

or

<cpu number>-<cpu number>

(must be a positive range in ascending order) or a mixture

<cpu number>,...,<cpu number>-<cpu number>

This option can be used to specify one or more CPUs to isolate from the general SMP balancing and scheduling algorithms. You can move a process onto or off an "isolated" CPU via the CPU affinity syscalls or cpuset.

<cpu number> begins at 0 and the maximum value is "number of CPUs in system - 1".

This option is the preferred way to isolate CPUs. The alternative -- manually setting the CPU mask of all   tasks in the system -- can cause problems and suboptimal load balancer performance.

Taken from /usr/share/doc/kernel-doc-2.6.32/Documentation/kernel-parameters.txt

Boot parameters of the running kernel in Linux

Let's say I need to find out with what parameters did the kernel boot?

The following command will give you the answer:

cat /proc/cmdline

For example:

janeiros@harlie:~$ cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.0.0-32-generic-pae root=/dev/mapper/harlie-root ro quiet


Wednesday, January 15, 2014

Fedora Full List of Kernel Options

The full list of kernel options is in the file /usr/share/doc/kernel-doc-<version>/Documentation/kernel-parameters.txt, which is installed with the kernel-doc package.

Taken from:
https://fedoraproject.org/wiki/Common_kernel_problems#Getting_the_Full_List_of_Kernel_Options