Iperf 2.0.10+ uses clock_gettime() when a timestamps is needed. For TCP and no interval reporting the only calls needed are at the beginning and end of the tes

Iperf 2.0.10+ uses clock_gettime() when a timestamps is needed. For TCP and no interval reporting the only calls needed are at the beginning and end of the test. The performance problem we hit with 2.0.5 had to do with insufficient shared memory between traffic threads and the reporter thread.