To determine eden length, one parameter to G1 size the eden is a prediction of whether the to-be-copied bytes of the currently examined length would actually fit into the currently available number of free regions to avoid allocation failures.

That prediction (effectively) multiplies the predicted number of bytes to copy for a given young gen length by 2.10. This is very conservative, and can unnecessarily limit the eden (increase gc frequency).

Try to improve this prediction without increasing the allocation failure occurrences too much.

One obvious option is to limit this prediction by the young region length.