Jim,
I never tried profiling before, so I ran into some problem here:
$ gcc -pg -o tstloop tstloop.c
$ tstloop
128205.13 semop/s [0,0]
$ gprof tstloop
gprof: gmon.out file is missing call-graph data

Any ideas?

As far as use of time vs. gettimeofday (which, in fact I did use) is quite irrelevant, I am trying to see how many times per second system is capable of creating a process which would simply read a semaphore.

Thanks.