JDK-8317987: C2 recompilations cause high memory footprint

[tstuefe]

While playing with the new compiler memory statistic (#16076), I saw that +StressRecompile causes a twofold increase in memory used during compilations.

Baseline:

highest peak during compilation is ~60 MB, caused by compilation of java/lang/invoke/LambdaForm$Kind::<clinit> with ~18k nodes.

./images/jdk/bin/java -XX:CompileCommand='collectmemstat,*.*' -XX:-StressRecompilation -Xcomp -Xbatch -cp $REPROS_JAR de.stuefe.repros.Simple

total     NA        RA        #nodes  time    type  #rc thread              method
(3/1425)
59063K    13406K    40025K    18345   6,174   c2    2   0x00007fdc2c28e7b0  java/lang/invoke/LambdaForm$Kind::<clinit>(()V) 

+StressRecompile:

highest peak during compilation is ~112 MB, same method, sameish node count.

./images/jdk/bin/java -XX:CompileCommand='collectmemstat,*.*' -XX:+StressRecompilation -Xcomp -Xbatch -cp $REPROS_JAR de.stuefe.repros.Simple

total     NA        RA        #nodes  time    type  #rc thread              method
(16/1434)
112M      13469K    94987K    18791   16,451  c2    2   0x00007f790428e7b0  java/lang/invoke/LambdaForm$Kind::<clinit>(()V) 

60M -> 112M. In both cases, a large part of the memory was allocated in resource areas. Its relative size compared to the total spike size increased. We accrue a lot of memory in ResourceArea over recompilations.

The solution is to wrap the Compile instantiation into a resource mark. Now we are at 61 MB, which is almost baseline:

total     NA        RA        #nodes  time    type  #rc thread              method
(3/1430)
61203K    13469K    40791K    18791   17,013  c2    2   0x00007fdf7428e7b0  java/lang/invoke/LambdaForm$Kind::<clinit>(()V) 

---

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Issue

• JDK-8317987: C2 recompilations cause high memory footprint (Bug - P4)

Reviewers

• Andrew Dinn (@adinn - Reviewer)
• Vladimir Kozlov (@vnkozlov - Reviewer)

Reviewing

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[tstuefe]

MacOs test error unrelated.

[mlbridge]

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• 00: Full (93170c17)

[adinn]

The holy grail of a 1-line fix that halves related memory footprint. Nice work!

[openjdk]

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

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

8317987: C2 recompilations cause high memory footprint

Reviewed-by: adinn, kvn

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At the time when this comment was updated there had been 7 new commits pushed to the master branch:

• c1f698d: 8317956: Make jdk.internal.util.Architecture current architecture final
• 9355431: 8316426: Optimization for HexFormat.formatHex
• 32ccf01: 8317772: NMT: Make peak values available in release builds
• 4c79e7d: 8170817: G1: Returning MinTLABSize from unsafe_max_tlab_alloc causes TLAB flapping
• 7633a76: 8317998: Temporarily disable malformed control flow assert to reduce noise in testing
• 00ef9f9: 8316947: Write a test to check textArea triggers MouseEntered/MouseExited events properly
• 77dc891: 8317963: Serial: Remove unused GenerationIsInReservedClosure

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[tstuefe]

The holy grail of a 1-line fix that halves related memory footprint. Nice work!

Yes, sometimes one still finds a free lunch :)

Thanks for the review.

[vnkozlov]

Nice. We added a lot of C2 recompilation cases for the past few years so it become noticeable.
The main ResourceMark for all JIT compilers is located in CompileBroker::invoke_compiler_on_method(): compileBroker.cpp#L2141

[tstuefe]

Thanks @vnkozlov and @adinn!

/integrate

[openjdk]

Going to push as commit c88b387.
Since your change was applied there have been 17 commits pushed to the master branch:

• 993951b: 8316464: 3 sun/tools tests ignore VM flags
• 17535c3: 8317818: Combinatorial explosion during 'this' escape analysis
• 61ce739: 8315484: java/awt/dnd/RejectDragDropActionTest.java timed out
• 77fa44f: 8317847: Typo in API documentation of class JPopupMenu
• 0983b54: 8318038: ProblemList runtime/CompressedOops/CompressedClassPointers.java on two platforms
• 64ee3c9: 8317266: Move nmethod::check_all_dependencies to codeCache.cpp and mark it NOT_PRODUCT
• 32ac72c: 8312522: Implementation of Foreign Function & Memory API
• 9728e21: 8317967: Enhance test/jdk/javax/net/ssl/TLSCommon/SSLEngineTestCase.java to handle default cases
• a8473b7: 8317336: Assertion error thrown during 'this' escape analysis
• 16fd43c: 8316693: Simplify at-requires checkDockerSupport()
• ... and 7 more: https://git.openjdk.org/jdk/compare/d95b548c78d2c504ccc3044f434f83e5c8237b0e...master

Your commit was automatically rebased without conflicts.

[openjdk]

@tstuefe Pushed as commit c88b387.

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