It would be interesting during G1 Full GC to get a summary about the work that has been done at region level.

E.g. how many regions were compacted, how many were not compacted (because pinned, too full, ...), and how many were completely skipped.

Particularly after recent changes in JDK-8262068 where regions are not compacted because they are too full this can be interesting (i.e. how much space do we actually waste?)