From JDK-8316226:

[...] pursue improvements to the basic algorithm [...]

[...] work will entail at least characterizing the specific configuration of our generational system where earlier promotions cost space in the old generation that shrinks the headroom for the young generation causing an increase in minor GC frequency. This calls for a strategy that is also cognizant not only of the low mortality of a cohort that is identified for promotion, but the cost of that promotion because of stranding that memory until a major collection cycle occurs in the future. In heap constrained scenarios, the resulting increase in major and minor collections can easily overwhelm the time saved in marking fewer objects in a minor cycle. I would like to model this system at a high level and try and determine what the analytical model determines to be the population that should be tenured at each cycle, based on an assumed simple lifetime distribution of objects, which is likely to be a function of the instantaneous sizes and occupancies of the old and the young generation.

[...] filed for that modeling and experimentation exercise.