OProfile is a system-wide profiler for Linux systems, capable of
profiling all running code at low overhead. OProfile is released
under the GNU GPL.

It consists of a kernel driver and a daemon for collecting sample
data, and several post-profiling tools for turning data into
information.

OProfile leverages the hardware performance counters of the CPU to
enable profiling of a wide variety of interesting statistics, which
can also be used for basic time-spent profiling. All code is
profiled: hardware and software interrupt handlers, kernel modules,
the kernel, shared libraries, and applications.