Stress is a tool which imposes a configurable amount of CPU, memory, I/O, or disk stress on a POSIX-compliant operating system. Stress is written in highly-portable ANSI C, and uses the GNU Autotools to compile on a great number of UNIX-like operating systems.

Stress is not a benchmark, it is rather a tool which puts the system under a repeatable, defined amount of load so that a systems programmer or system administrator can analyze the performance characteristics of the system or specific components thereof.