The onto:measurement in GraphDB reports the values in milliseconds. In this system, the total time for an event is the sum of all individual timing intervals recorded for that event. For cases with nested measurements, a net execution time is computed by subtracting the time spent in nested events from the total time.

For further technical details on onto:measurement, please refer to official GraphDB documentation, which is regularly enriched with additional information:
https://graphdb.ontotext.com/documentation