You can set a trace to filter out events that do not occur during a specified time. For example, if you want to view an event that started between 2:00 A.M. and 2:30 A.M., you can set a trace to automatically filter out all events starting before 2:00 A.M. and after 2:30 A.M. Start Time and End Time filters capture events that occur only between the specified times. The trace itself is active during the time and does not autostart or stop at the Start Time and End Time. These times affect only the filter.
How to set a Start Time filter for a trace
How to set an End Time filter for a trace