What is the best way to calculate the running time of a multi-process program?

Question

I have a multi-process program written in C , where the parent forks a number of children, and I need to calculate its running time, and compare it with the running time of a multi-threaded program which does the same task as that by the multi-process one.

Except using time.h 's clock function (which reports CPU time, thus may report more time in a multi-threaded program if no. of threads is high), what else can I use to calculate both programs' running time for comparison purposes ?

I am currently using time ./a.out to calculate their running time.

Answer 1

Just use gettimeofday() from the time library on the main thread and it should give you its elapsed time.

If you run it on a thread it will only reply back with that particular threads elapsed time.