Why does MySQL have over 100% CPU usage?

Question

Why does MySQL have over 100% CPU usage?

Answer

MySQL is a multi-threaded process that spreads its usage over multiple cores. Because of this, it is normal for it to have over 100% CPU usage.

Additional resources

MySQL FAQ: Does MySQL work with multi-core processors?

Why is the CPU usage for a process over 100%?

Is there an easy method for doing MySQL tuning?