8277865: G1: Change integer division to floating point division

[lkorinth]

In the class G1PreConcurrentStartTask::NoteStartOfMarkTask the method worker_cost returns a cost of type double, unfortunately the return value is calculated using an integer division:

return _claimer.n_regions() / regions_per_thread;

---

Progress

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Issue

• JDK-8277865: G1: Change integer division to floating point division

Reviewers

• Albert Mingkun Yang (@albertnetymk - Reviewer)
• Thomas Schatzl (@tschatzl - Reviewer)

Reviewing

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[mlbridge]

Webrevs

• 00: Full (e2ddb0bc)

[openjdk]

@lkorinth 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:

8277865: G1: Change integer division to floating point division

Reviewed-by: ayang, tschatzl

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At the time when this comment was updated there had been 46 new commits pushed to the master branch:

• 3d810ad: 8277411: C2 fast_unlock intrinsic on AArch64 has unnecessary ownership check
• ce0234b: 8277860: PPC: Remove duplicate info != NULL check
• 040b2c5: 8277139: Improve code readability in PredecessorValidator (c1_IR.cpp)
• 3e798dd: 8275330: C2: assert(n->is_Root() || n->is_Region() || n->is_Phi() || n->is_MachMerge() || def_block->dominates(block)) failed: uses must be dominated by definitions
• 99e4bda: 8277417: C1 LIR instruction for load-klass
• 00a6238: 8277508: need to check has_predicated_vectors before calling scalable_predicate_reg_slots
• 3383c0d: 8277659: [TESTBUG] Microbenchmark ThreadOnSpinWaitProducerConsumer.java hangs
• 7e54d06: 8277165: jdeps --multi-release --print-module-deps fails if module-info.class in different versioned directories
• eb4d886: 8277504: Use String.stripTrailing instead of hand-crafted method in SwingUtilities2
• 9879920: 8277825: Remove unused ReferenceProcessorPhaseTimes::_sub_phases_total_time_ms
• ... and 36 more: https://git.openjdk.java.net/jdk/compare/79350b9b4f42e43a8ab27ea76b9115dae6f448af...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.

[tschatzl]

Lgtm.

[lkorinth]

/integrate

[openjdk]

Going to push as commit 9a3a9b1.
Since your change was applied there have been 53 commits pushed to the master branch:

• aed53ee: 8264838: IGV: enhance graph export functionality
• 0c7a4b8: 8277842: IGV: Add jvms property to know where a node came from
• c3a7f2f: 8277382: make c1 BlockMerger use IR::verify only when necessary
• 8f9eb62: 8274784: jshell: Garbled character was displayed by System.out.println(...) on Japanese Windows
• e9b36a8: 8276670: G1: Rename G1CardSetFreePool and related classes
• b9eb532: 8276685: Malformed Javadoc inline tags in JDK source in /jdk/management/jfr/RecordingInfo.java
• 40fef23: 8275908: Record null_check traps for calls and array_check traps in the interpreter
• 3d810ad: 8277411: C2 fast_unlock intrinsic on AArch64 has unnecessary ownership check
• ce0234b: 8277860: PPC: Remove duplicate info != NULL check
• 040b2c5: 8277139: Improve code readability in PredecessorValidator (c1_IR.cpp)
• ... and 43 more: https://git.openjdk.java.net/jdk/compare/79350b9b4f42e43a8ab27ea76b9115dae6f448af...master

Your commit was automatically rebased without conflicts.

[openjdk]

@lkorinth Pushed as commit 9a3a9b1.

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