EMA C++ Performace Tools Guide : 6 Non-Interactive Provider Performance Tool : 6.4 Latency Measurement
 
6.4 Latency Measurement
EmaCppNIProvPerf encodes a timestamp as part of its message payload. The timestamp is taken at the start of encoding and added as field TIM_TRK_1 (3902). Latency is measured after a Consumer Performance tool decodes the message and payload.
Non-Interactive Provider Latency Measurement Sequence:
1. Get the current time (t1).
2. Encode the message, including time t1.
3. Pass the message to the API, which passes it to underlying transport.
4. The consuming application receives a timestamp in the payload and compares it to the current time to calculate latency.