8331907: BigInteger and BigDecimal should use optimized division

[djelinski]

Replace the custom unsigned divide / remainder functions with the compiler-optimized Long.divideUnsigned / remainderUnsigned.

No new tests. Existing tier1-3 tests continue to pass.

I added a new set of divide benchmarks. Results in thread.

I also removed the BigDecimal.toString benchmarks. They no longer serve their purpose - toString caches the returned value, so we were only benchmarking the cache access time.

---

Progress

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Issue

• JDK-8331907: BigInteger and BigDecimal should use optimized division (Enhancement - P4)

Reviewers

• Raffaello Giulietti (@rgiulietti - Reviewer)
• Brian Burkhalter (@bplb - Reviewer)

Reviewing

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Update a local copy of the PR:
$ git checkout pull/19134
$ git pull https://git.openjdk.org/jdk.git pull/19134/head

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$ git pr checkout 19134

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[bridgekeeper]

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[openjdk]

@djelinski 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:

8331907: BigInteger and BigDecimal should use optimized division

Reviewed-by: rgiulietti, bpb

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 79 new commits pushed to the master branch:

• 5ded8da: 8332085: Remove 10 year old transition check in GenerateCurrencyData tool
• 7c2c24f: 8261433: Better pkcs11 performance for libpkcs11:C_EncryptInit/libpkcs11:C_DecryptInit
• ff4bf1c: 8332102: Add @since to package-info of jdk.security.jarsigner
• abf54bb: 8332100: Add missing @since to KeyValue::EC_TYPE in java.xml.crypto
• 1484153: 8332080: Update troff man page for javadoc
• 391bbbc: 8330584: IGV: XML does not save all node properties
• adaa509: 8327499: MethodHandleStatics.traceLambdaForm includes methods that cannot be generated
• 5a8df41: 8331535: Incorrect prompt for Console.readLine
• 3e3f7cf: 8330387: Crash with a different types patterns (primitive vs generic) in instanceof
• d517d2d: 8331764: C2 SuperWord: refactor _align_to_ref/_mem_ref_for_main_loop_alignment
• ... and 69 more: https://git.openjdk.org/jdk/compare/a8b3f194e811eed6b20bce71c752705c7cd50d24...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[openjdk]

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[djelinski]

Results before:

Benchmark                                   Mode  Cnt    Score   Error  Units
BigDecimals.testHugeLargeDivide             avgt   15  115.176 ± 0.965  ns/op
BigDecimals.testHugeSmallDivide             avgt   15   82.652 ± 0.601  ns/op
BigDecimals.testLargeSmallDivide            avgt   15    6.601 ± 0.320  ns/op
BigIntegers.testHugeLargeDivide             avgt   15   53.905 ± 0.734  ns/op
BigIntegers.testHugeSmallDivide             avgt   15   52.762 ± 0.354  ns/op
BigIntegers.testLargeSmallDivide            avgt   15   22.990 ± 0.058  ns/op

after:

Benchmark                                   Mode  Cnt    Score   Error  Units
BigDecimals.testHugeLargeDivide             avgt   15  106.549 ± 0.695  ns/op
BigDecimals.testHugeSmallDivide             avgt   15   68.339 ± 0.172  ns/op
BigDecimals.testLargeSmallDivide            avgt   15    6.594 ± 0.328  ns/op
BigIntegers.testHugeLargeDivide             avgt   15   29.576 ± 0.411  ns/op
BigIntegers.testHugeSmallDivide             avgt   15   30.072 ± 0.242  ns/op
BigIntegers.testLargeSmallDivide            avgt   15    8.034 ± 0.078  ns/op

[mlbridge]

Webrevs

• 03: Full - Incremental (ec680946)
• 02: Full - Incremental (83a9959a)
• 01: Full - Incremental (a3fbc07d)
• 00: Full (e565e1b6)

[rgiulietti]

There's another spot for replacement at L.1096-1097 in MutableBigInteger. Did you see that one?

[djelinski]

L.1096-1097 is a 32-bit by 32-bit division; I guess I could change it to use Integer.unsignedDivide. Let me look into it...

[rgiulietti]

LGTM

[bplb]

I have nothing to add to the comments already resolved. +1

[djelinski]

Thanks for the reviews!

/integrate

[openjdk]

Going to push as commit beea530.
Since your change was applied there have been 80 commits pushed to the master branch:

• 440782e: 8331466: Problemlist serviceability/dcmd/gc/RunFinalizationTest.java on generic-all
• 5ded8da: 8332085: Remove 10 year old transition check in GenerateCurrencyData tool
• 7c2c24f: 8261433: Better pkcs11 performance for libpkcs11:C_EncryptInit/libpkcs11:C_DecryptInit
• ff4bf1c: 8332102: Add @since to package-info of jdk.security.jarsigner
• abf54bb: 8332100: Add missing @since to KeyValue::EC_TYPE in java.xml.crypto
• 1484153: 8332080: Update troff man page for javadoc
• 391bbbc: 8330584: IGV: XML does not save all node properties
• adaa509: 8327499: MethodHandleStatics.traceLambdaForm includes methods that cannot be generated
• 5a8df41: 8331535: Incorrect prompt for Console.readLine
• 3e3f7cf: 8330387: Crash with a different types patterns (primitive vs generic) in instanceof
• ... and 70 more: https://git.openjdk.org/jdk/compare/a8b3f194e811eed6b20bce71c752705c7cd50d24...master

Your commit was automatically rebased without conflicts.

[openjdk]

@djelinski Pushed as commit beea530.

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