How to make Eden Space size double Tenured Space

Question

Is there any way to make the Eden space proportionally bigger than Tenured? There is NewRatio but it works the other way (Tenured is that times bigger than Eden).

I know there is -XX:NewSize= and -XX:OldSize= but I was looking for something similar to mentioned ratio parameter (which would give more flexibility).

I've tried using fraction but it's not valid value.

Answer 1

Similar to the total heap size (with -Xms and -Xmx) it is possible to explicitly set a lower and upper bound for the size of the young generation. However, when setting -XX:MaxNewSize we need to take into account that the young generation is only one part of the heap and that the larger we choose its size the smaller the old generation will be. For stability reasons it is not allowed to choose a young generation size larger than the old generation, because in the worst case it may become necessary for a GC to move all objects from the young generation into the old generation. Thus -Xmx/2 is an upper bound for -XX:MaxNewSize.

For performance reasons we may also specify the initial size of the young generation using the flag -XX:NewSize. This is useful if we know the rate at which young objects are being allocated (for example because we measured it!) and can save some of the costs required for slowly growing the young generation to that size over time.

My answer is based on this blog.