Linux perf events: cpu-clock and task-clock - what is the difference

Question

Linux perf tools (some time ago named perf_events) has several builtin universal software events. Two most basic of them are: task-clock a

Answer 1

Generally speaking: The cpu-clock event measures the passage of time. It uses the Linux CPU clock as the timing source.

Here is an in-depth article on finding execution hot spots with perf: http://sandsoftwaresound.net/perf/perf-tutorial-hot-spots/

The task-clock tells you how parallel your job has been/how many cpus were used. This compendium contains detaild information of output generated by perf: https://doc.zih.tu-dresden.de/hpc-wiki/bin/view/Compendium/PerfTools

There is also a whole lot of information here: https://stackoverflow.com/a/20378648/8223204