Updated version of an article first published on February 24th, 2015. Your Linux server is running slow, so you follow standard procedure and run top. You see the CPU metrics: But what do all of those 2-letter abbreviations mean? The 3 CPU states Let’s take a step back. There are 3 general states your CPU can be in: Idle, which means it has nothing to do. Running a user space program, like a comma