moncontrol() - turns on/off profiling during execution
void moncontrol( int on );
If passed 1, moncontrol() enables profiling. If passed 0,
moncontrol() disables profiling. It can be called many
times during execution, typical use is to profile only
certain parts of driver execution. moncontrol() has no
effect if profiling is not enabled at driver compile time.
opcprof(3), function_profile(3)