RFR: 8348278: Trim InitialRAMPercentage to improve startup in default modes [v4]

[Stefan Johansson]

On Wed, 17 Sep 2025 15:58:05 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> In other words, the reasonable-on-a-surface idea of capping at Xms2g turns out to be the worst default for a default collector, because it almost always does Xmx=Xms on a large-ish machine, like my desktop :) In other words, for G1, 2G Xms cap is way, way too high.

This adds another argument to something else we discussed yesterday, why is this initial value a fraction of the RAM and not a fraction of the chosen `MaxHeapSize`? We could not come up with a good answer to that, do you see any good reason?

-------------

PR Comment: https://git.openjdk.org/jdk/pull/23262#issuecomment-3305579549