The times that are reported are the times that the event in question occurred. For all system calls, the event is the completion of the system call, not the start of the system call. Includes a time delta on each line of trace out- put. The value appears as a field containing seconds . Specifically, for system calls, this is not the time spent within the system call.
System calls to trace or exclude.
Those system calls specified in the comma-separated list are traced. Default is -tall. System calls that stop the process. The specified system calls are added to the set specified by -t. That is, truss releases the process and exits but leaves the process in the stopped state at completion of the system call in question.