%% [[Software Development]] [[Software Testing]] [[Software Engineering]] %% - [[Joe Colantonio]] talks about CPU (utilization) as the pulse rate of the system. CPU it often the most obvious indicator of performance failures and bottlenecks. - [[Performance Testing Basics What Is Resource Utilization]] - "`CPU utilization measurements can help determine how effective your test is. It can also be used as a gauge of how any tuning change you've made has affected the overall performance of the system. I like to think of CPU as the pulse rate in the overall health of a system. `" - It is important to check the CPU utilization on both the application servers as well as the load generators. We don't want CPU utilization to be 100% at any point, because that means that the CPU is struggling to send or process requests. As a general rule of thumb, continuous CPU utilization of 80% or above is considered unhealthy. - "`When the CPU hits 100% it can no longer process more work and your throughput flattens. Usually, a best practice would be to avoid 80% CPU utilization for each processor for long periods of time.`" - [[Getting CPU Utilization in Windows]] - [[Getting CPU Utilization on UNIX]] - [[Getting CPU Utilization on a Mac]]