Abstract: The present invention overcomes many of the disadvantages associated with the prior art by providing an automated, real time performance monitoring facility which runs periodically as a background process in a computer system. This invention preferably uses performance data collection sites already present in the hardware of the computer system, microcode and/or operating system software. At a user selectable period of time, a sampling of key performance factors is taken from the performance data collection sites. The performance monitor then analyzes the, sampled results by comparing the collected results against two or more performance threshold levels (such as early warning or actual performance limiters) for each performance criteria.