stress is a simple tool that imposes a configurable amount of CPU, memory,
I/O, and disk stress on POSIX-compliant operating systems. It is written in
portable ANSI C, and uses the GNU Autotools to compile on most UNIX-like
operating systems.

stress is not a benchmark. It is a tool used by system administrators to
evaluate how well their systems will scale, by kernel programmers to evaluate
perceived performance characteristics, and by systems programmers to expose
the classes of bugs which only or more frequently manifest themselves when the
system is under heavy load.