Thursday, November 17, 2005

Disabling CPUs on Linux - Part One

For running performance tests and to determine the potential benefit of additional CPUs it can be very helpful to be able to disable CPUs. CPU's can be disabled by adding the following clause to the kernel configuration line in the grub.conf configuration line:
maxcpus=<NUM_CPUS>
The placeholder NUM_CPUS has to be replaced with the number of CPUs that will be enabled. After re-booting with the correct kernel verify that the correct number of CPUs are active. This can be verified with the file /proc/cpuinfo.

1 comment:

Mat said...

does this only disable them though? My concern is that the cores would be powered and running, just not used or "seen" by Linux.