RFR: 8321815: Shenandoah: gc state should be synchronized to java threads only once per safepoint

[Kelvin Nilsen]

On Thu, 14 Dec 2023 19:14:07 GMT, William Kemper <wkemper at openjdk.org> wrote:

> Presently, every change to the gc change is distributed to all java threads. The gc state is only changed on safepoints. For applications with a very large number of java threads this may increase time on the safepoint. It would be better to synchronize the gc state only once per safepoint.

Am wondering if we measure any improvement in time-at-safepoints for workloads with large number of threads?

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Marked as reviewed by kdnilsen (no project role).

PR Review: https://git.openjdk.org/jdk/pull/17112#pullrequestreview-1782569774