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8265411: Avoid unnecessary Method::init_intrinsic_id calls #3564


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@iklam iklam commented Apr 19, 2021

check_methods_for_intrinsics() in classFileParser.cpp calls Method::klass_id_for_intrinsics() to see if a class has intrinsic methods. However, the latter returns any class whose name is included in vmSymbols. This causes many unnecessary calls to Method::init_intrinsic_id().

To fix this, we precompute the classes that are known to have intrinsics using constexpr. See vmIntrinsics::class_has_intrinsics.

After the fix, when running java -Xshare:off -version, the number of classes initialized for intrinsics is reduced from 130 to 30.

Testing: mach5 tiers 1~4 passed.


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  • JDK-8265411: Avoid unnecessary Method::init_intrinsic_id calls



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@bridgekeeper bridgekeeper bot commented Apr 19, 2021

👋 Welcome back iklam! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

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@openjdk openjdk bot commented Apr 19, 2021

@iklam The following label will be automatically applied to this pull request:

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@openjdk openjdk bot added the hotspot label Apr 19, 2021
@iklam iklam marked this pull request as ready for review Apr 19, 2021
@iklam iklam closed this Apr 19, 2021
@iklam iklam reopened this Apr 19, 2021
@openjdk openjdk bot added the rfr label Apr 19, 2021
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@mlbridge mlbridge bot commented Apr 19, 2021


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@dholmes-ora dholmes-ora left a comment

Hi Ioi,

That all appears fine to me.

Is there any startup impact?


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@openjdk openjdk bot commented Apr 20, 2021

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

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

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

8265411: Avoid unnecessary Method::init_intrinsic_id calls

Reviewed-by: dholmes, minqi

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@openjdk openjdk bot added the ready label Apr 20, 2021
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@iklam iklam commented Apr 20, 2021

Hi Ioi,

That all appears fine to me.

Is there any startup impact?


Hi David, when CDS is turned off, I can see a small improvement in start-up, due to the reduction in intrinsic ID lookup:

$ perf stat -r 100 bin/java -Xshare:off -Xint -version

OLD: 191,632,128 cycles 0.074624 sec
NEW: 191,387,603 cycles 0.073704 sec

With CDS enabled, the intrinsic ID lookup is done during archive dump time, so this PR makes no difference.

Also, the lookup table itself is generated during C++ compilation, so it has no runtime impact:

	.section	.rodata
	.type	_ZL18_intrinsics_lookup, @object
	.byte	0
	.byte	0
	.byte	1
	.byte	1

yminqi approved these changes Apr 20, 2021
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@yminqi yminqi left a comment

LGTM, thanks for fixing this!

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@yminqi yminqi commented Apr 20, 2021

BTW, the the fix works for the problem: adding symbols to vmSymbols.hpp caused debug build failed due to this bug.

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@iklam iklam commented Apr 21, 2021

Thanks @dholmes-ora and @yminqi for the review!

@openjdk openjdk bot closed this Apr 21, 2021
@openjdk openjdk bot added integrated and removed ready rfr labels Apr 21, 2021
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@openjdk openjdk bot commented Apr 21, 2021

@iklam Since your change was applied there have been 15 commits pushed to the master branch:

  • a22ad03: 8264983: Add gtest for JDK-8264008
  • 91b08b7: 8261779: JCK test api/javax_crypto/EncryptedPrivateKeyInfo/Ctor4.html is failing with assertion error when assertions enabled
  • 2fcd920: 8261183: Follow on to Make lists of normal filenames
  • 40ef00c: 8258457: testlibrary_tests/ctw/ fails with InvalidPathException on windows
  • 3f0da35: 8261392: Exclude testlibrary_tests/ctw/
  • 8d0faaf: 8257001: Improve Http Client Support
  • 9bf055d: 8259633: compiler/graalunit/ fails with NPE after JDK-8244543
  • ddc56d1: 8259428: AlgorithmId.getEncodedParams() should return copy
  • ae33d2a: 8258247: Couple of issues in fix for JDK-8249906
  • 2003e91: 8244543: Enhanced handling of abstract classes
  • ... and 5 more:

Your commit was automatically rebased without conflicts.

Pushed as commit 739769c.

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