Thread mode

This view mode is optimized for interpreting programs that make explicit use of pthreads. Percentage values and activity graphs reflect the proportion of CPU cores that are being used out of the maximum number of expected cores per process, see Processes and cores window.

A value of 100% for a function or line means that 100% of the expected number of CPU cores per process were working at that location. The main thread’s contribution gets no special attention so activity on the main thread(s) will appear the same height as activity from any other thread.

The advantage of this is that it makes it obvious when the program is not making full use of all the CPU cores available to it. The disadvantage is that it is harder to analyze the performance of the intentionally serial sections of code performed by each process. This is because activity occurring only on one thread per process will be restricted to at most 1/n^th of a percentage value or height on an activity graph, where n is the number of cores per process.

This mode is not used by default so must be explicitly selected. It is only available for multithreaded programs.

The OpenMP Regions view is not displayed in this mode.