"Before we can begin to improve the performance of our system, we need to use the monitoring tools available to us to baseline. Here are some monitoring tools you should consider using: Oprofile
"This tool (made available in RHEL5) utilizes the processor to retrieve kernel system information about system executables. It allows one to collect samples of performance data every time a counter detects an interrupt. I like the tool also because it carries little overhead – which is very important because you don't want monitoring tools to be causing system bottlenecks."
