in addition to looking to the log timestamps as suggested by Mahesh, if this a testing lab scenario and you have a traffic generator instrument, you could send traffic from network1 to network2 doing a frame loss test.
Given a constant TX packet rate (i.e. for example 1000 packets/s) the number of packets lost during TE FRR switchover will give you a measure of network convergence time from the point of view of user traffic,
This would be a meaningful test.
Hope to help