While reviewing various G1 GC logs of ATG CRM it was noticed that the pause times for mixed GCs were quite a bit larger than corresponding young GCs. It was also noticed that the mixed GCs in a series were getting progressively longer and longer.

This makes sense as the set of regions that will be collected during an individual series of mixed GCs is sorted according to decreasing GC efficiency. This means that regions at the head of the sorted list have a higher GC efficiency than those at the tail.

Since we choose the old regions to be included in a mixed GC from this list left to right - later mixed GCs in the series are choose regions that are more expensive to collect.

The current mixed GC policy basically collects a fixed fraction of the "candidate" regions each mixed GC.

This policy is inadequate. As progress through the mixed GC series, it takes longer and longer to collect the regions in the fixed fraction.

An alternative to the current policy should be investigated.