[Bugfix] [Tiered Caching] Add segmented locks to TieredSpilloverCache

[peteralfonsi]

Description

In performance benchmarking of tiered caching we found the TSC spends a lot of its time waiting on a single global read-write lock, which blocks access to the underlying cache. This lock is meant to prevent keys from entering both the on-heap and disk tier simultaneously; the underlying tiers themselves are threadsafe.

To resolve this, we effectively segment the TSC with 256 locks. To do a cache operation with a key, you must acquire the corresponding lock, which is determined by key.hashCode(). This way most pairs of keys can access the cache concurrently.

Related Issues

Part of tiered caching.

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
    - [N/A] API changes companion pull request created.
• Failing checks are inspected and point to the corresponding known issue(s) (See: Troubleshooting Failing Builds)
• Commits are signed per the DCO using --signoff
  - [N/A] Commit changes are listed out in CHANGELOG.md file (See: Changelog)
  - [N/A] Public documentation issue/PR created

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[github-actions]

❌ Gradle check result for 0373056: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❌ Gradle check result for 4dea454: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[peteralfonsi]

Flaky test:
#13600
and timeout in same suite