RFR: 8346920: Serial: Support allocation in old generation before GC

Thu Jan 2 06:38:43 UTC 2025

This PR introduces a new strategy to determine whether an allocation should be attempted in the old generation or if a GC cycle should be initiated, based on the `GCTimeRatio`. With this change, the benchmark attached to the ticket now completes in ~13 GC, a significant improvement compared to the >1000 GC observed previously.

Test: tier1-3

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Commit messages:
 - s1-gc-time-ratio

Changes: https://git.openjdk.org/jdk/pull/22899/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22899&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8346920
  Stats: 26 lines in 3 files changed: 23 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/22899.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22899/head:pull/22899

PR: https://git.openjdk.org/jdk/pull/22899