Provides a low-resolution (10 milliseconds) time stamp but is comparatively less expensive to retrieve. System time is the ...

Provides a low-resolution (10 milliseconds) time stamp but is comparatively less expensive to retrieve. System time is the default.  Note that if the volume of events is high, the resolution for system time may not be fine enough to determine the sequence of events. In this case, a set of events will have the same time stamp, but the order in which the events are delivered may not be correct.  In this case the local sequence number can be used to determine the order.