8349457: [leyden] Workaround Leyden problems with -XX:-TieredCompilation

[shipilev]

Currently, supplying -XX:-TieredCompilation would break with Leyden workflows, because the archive-backed code cache heap would only be created if SegmentedCodeCache is enabled. With default compilation policy, this happens normally when tiered compilation is enabled, but not without it.

There are other minor peculiarities that we need to handle, which are exposed with runtime/cds + -XX:-TieredCompilation runs.

This prevents us from testing C2-only Leyden configs and studying compilation dynamics without tiered policy getting in the way.

Additional testing:

• Ad-hoc Leyden experiments now work with -XX:-TieredCompilation: the C2-only code is being stored and loaded successfully from the CDS archive
• runtime/cds now passes with -XX:-TieredCompilation
• runtime/cds still passes by default (i.e. with tiered compilation)

---

Progress

• Change must not contain extraneous whitespace
• Change must be properly reviewed (1 review required, with at least 1 Committer)

Issue

• JDK-8349457: [leyden] Workaround Leyden problems with -XX:-TieredCompilation (Bug - P4)

Reviewers

• Ashutosh Mehra (@ashu-mehra - Committer) ⚠️ Review applies to 1ee3b847
• Igor Veresov (@veresov - Committer) ⚠️ Review applies to 1ee3b847
• Vladimir Ivanov (@iwanowww - Committer)

Reviewing

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[bridgekeeper]

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[openjdk]

@shipilev This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8349457: [leyden] Workaround Leyden problems with -XX:-TieredCompilation

Reviewed-by: asmehra, iveresov, vlivanov

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[mlbridge]

Webrevs

• 03: Full - Incremental (6cdde259)
• 02: Full - Incremental (ee4d9d11)
• 01: Full - Incremental (1ee3b847)
• 00: Full (0dcee32d)

[ashu-mehra]

lgtm

[vnkozlov]

@veresov should look on this.

[veresov]

@veresov should look on this.

@iwanowww wrote that particular part. I looks good to me though.

[shipilev]

Fun perf results:

$ build/linux-x86_64-server-release/images/jdk/bin/java -Xms64m -Xmx1g -XX:+UseParallelGC \
     -XX:CacheDataStore=JavacBenchApp.cds -cp JavacBenchApp.jar JavacBenchApp 50

# --- Training with C1 and C2 (+Tiered)

# Production with C1 and C2 (+Tiered)
  Time (mean ± σ):     434.0 ms ±   8.5 ms    [User: 1506.7 ms, System: 218.4 ms]
  Range (min … max):   423.4 ms … 449.2 ms    10 runs

# Production with C2 only (-Tiered)
  Time (mean ± σ):     561.2 ms ±  12.8 ms    [User: 3578.0 ms, System: 263.2 ms]
  Range (min … max):   542.3 ms … 589.2 ms    10 runs

# --- Training with C2 only (-Tiered)

# Production with C1 and C2 (+Tiered)
  Time (mean ± σ):     408.0 ms ±   5.4 ms    [User: 1183.2 ms, System: 165.2 ms]
  Range (min … max):   401.3 ms … 421.0 ms    10 runs

# Production with C2 only (-Tiered)
  Time (mean ± σ):     482.0 ms ±  11.6 ms    [User: 1959.1 ms, System: 182.5 ms]
  Range (min … max):   467.2 ms … 508.2 ms    10 runs

[shipilev]

Taking the rest of the week off, so feel free to integrate without me.

/integrate delegate

[openjdk]

@shipilev Integration of this pull request has been delegated and may be completed by any project committer using the /integrate pull request command.

[shipilev]

Current GHA failures should be fixed by #35.

[iwanowww]

Looks good.

[shipilev]

Thanks!

/integrate

[openjdk]

@shipilev
Your change (at version 6cdde25) is now ready to be sponsored by a Committer.

[vnkozlov]

/sponsor

[openjdk]

Going to push as commit 0a32077.

[openjdk]

@vnkozlov @shipilev Pushed as commit 0a32077.

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