These events describe a call to the PVM library. It contains a timestamp and the return value of the send call.
Most events come in pairs.
This allows one to determine the amount of time spent within a call. This will cause the calc program to be spawned with tracing turned on. Trace events will be sent to the PVM console and displayed there. Tracing of particular routines can be turned on or off by the PVM console. The second command turns on tracing for the barrier routine.