In GNU/Linux I use Intel’s PCM to monitor CPU utilization. I’m not sure if this works fine on OSX, but as far as I know the source-code is including the MacMSRDriver directory. I have no any OSX device, never test it anyway.
In case this source compiled on your device, Just run:
pcm.x -r -- your_program your_program_parameter
or if you want advanced profiling, use pcm-core.x instead or you can build your own code based on pcm-core.cpp