HowTo: Profiling LMDZ

Profiling with gprof =

The legacy way to profile the model is using gprof.

• Pros: available everywhere, easy to use
• Cons: old, bad handling of multithreaded applications, requires instrumentation

gprof is a rudimentary but simple to use tool to profile a sequential executable.

Instrumenting the code

In the .fcm arch file used, add -pg to BASE_FFLAGS and BASE_LD. Recompile the model.

Collecting statistics

Run the executable gcm.e. This will generate a gmon.out file locally.

Reading results

Run gprof gcm.e gmon.out > profiling.txt to get a textual view of the profiling.

For a graphical representation, we recommend using gprof2dot, via gprof gcm.e | gprof2dot | dot -Tpng -o output.png. A typical example is shown below.