# PE4 Tuning

Tuning means to change some system variables/configurations (without changing the program itself) in order to optimize the performance.

## Learning objectives

  *  Use profiling tools such as prof, gprof and line-by-line profilers.
  *  Define Amdahl's Law.
  *  Tune a parallel program in order to achieve better runtimes and to optimize the usage of the HPC resources.

## Subskills