I have an OpenMP program running with say 6 threads on a 8-core machine. How can I extract this information (num_threads = 6) from another program (non-openmp, plain C program). Can I get this info from underlying kernel.
I was using run_queue lengths using "sar -q 1 0" but this doesn't yield consistent results. sometimes it gives 8, few times more or less.
In Linux, threads are processes (see first post here), so you can ask for a list of running processes with ps -eLf. However, if the machine has 8 cores, it is possible that OpenMP created 8 threads (even though it currently uses 6 of them for your computation); in this case, it is your code that must store somewhere (e.g. a file, or a FIFO) information about the threads that it is using.
