Now-a-days, if you are tuning your GC you are almost certainly doing the wrong thing.

While the JVM offers a plethora of levers to pull in case you are hyper concerned about different things, the heuristics are VERY good. Mucking with the fine grained details can disable heuristics and ultimately give you worse results than if you just left stuff alone.

The levers to pull are algorithm, max memory, and max pause time. All other levers should be left alone unless you've got GC logs to back up what you think needs changing. (And even then... Do you really?)

Typically, the better route is flight recorder and eliminating wasted allocations.