Prioritize Processes and Allocate CPUs

Playing around nice and taskset to prioritize processes and allocate CPUs on a multi processor machine.

Hardware Overview

4 cpus: Intel(R) Xeon(R) CPU L5410 @ 2.33GHz

2GB RAM:

OS: CentOS 5.0 x86_64

Basic Concepts About nice and taskset

process priority: niceness value -20 to 19,

-20 is the highest priority

19 is the lowest priority

The following command will make the httpd process and all of its sub-process run as very high priority!

$ renice -15 -p HTTP-ROOT-PROCESS-PID -u HTTPD-USERNAME

cpu affinity: hex mask

0x0001 is the CPU 0

0x1000 is the CPU 3