The fix for 8017462 fixed the use of UseDynamicNumberOfGCThreads with G1. Part of the fix was to make the statistics calculated for different phases of the collection recognize that the number of parallel GC threads being used was dynamic. A test was written to check the use of G1 and UseDynamicNumberOfGCThreads indeed used a number of parallel GC threads that could be changing dynamically. Before the fix for 8017462 one failure mode was that guarantees failed during the calculation of statistics. This change adds a test to check that the sum of a per thread statistic matches the sum printed in the G1 GC log.