8355512: Test compiler/vectorization/TestVectorZeroCount.java times out with -XX:TieredStopAtLevel=3

[jaskarth]

Hi all,
This is a small patch to TestVectorZeroCount to make it only execute when C2 is enabled, to fix a timeout with -XX:TieredStopAtLevel=3. This test takes a long time to finish without C2 because it iterates through all of the integers twice. Since the intention of the test is to stress the C2-specific numberOfLeadingZeros and numberOfTrailingZeros intrinsics, I think it makes sense to limit it to running with C2 only.

Reviews would be appreciated!

---

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Issue

• JDK-8355512: Test compiler/vectorization/TestVectorZeroCount.java times out with -XX:TieredStopAtLevel=3 (Bug - P4)

Reviewers

• Christian Hagedorn (@chhagedorn - Reviewer)
• Emanuel Peter (@eme64 - Reviewer)

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8355512: Test compiler/vectorization/TestVectorZeroCount.java times out with -XX:TieredStopAtLevel=3

Reviewed-by: chagedorn, epeter

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• 265d630: 8357187: JFR: User-defined defaults should be respected when an incorrect setting is set
• 92fd449: 8350960: RISC-V: Add riscv backend for Float16 operations - vectorization
• 2e26b43: 8356875: RISC-V: extension flag UseZvfh should depends on UseZfh
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[chhagedorn]

Looks good, thanks for fixing it!

[eme64]

@jaskarth @chhagedorn Hmm, this means that this test could not be run with GraalVM, for example. That's a shame.
Do we not have some way to assert that there should be "some fast compiler"? Ah, what does vm.flavor == "server" do? Because I have seen lines like vm.flavor == "server" & !vm.graal.enabled before.

[jaskarth]

@eme64 I think vm.flavor == "server" ensures that the test runs on server-class VMs, but I wasn't sure if manually setting the TieredStopAtLevel changes that designation. I looked at some more tests and I saw that they were using @requires vm.flavor == "server" & (vm.opt.TieredStopAtLevel == null | vm.opt.TieredStopAtLevel == 4), which looks like a good way to check for any tier4 compiler. I've updated the patch to use that method instead, which should let it run on graal as well.

[eme64]

@jaskarth Thanks for doing the research on this, nice to see that there is a solution :)

[jaskarth]

@eme64 @chhagedorn Thanks a lot for the reviews! Does testing need to be run on this change, or can I integrate it?

[chhagedorn]

Good improvement!

[chhagedorn]

@eme64 @chhagedorn Thanks a lot for the reviews! Does testing need to be run on this change, or can I integrate it?

I think it's good to go in since you only exclude it from running in the problematic scenarios.

[eme64]

@jaskarth Thanks for asking. I'll run some testing, just to be safe :)

[jaskarth]

@eme64 Any results with testing? :)

[eme64]

@jaskarth All 🟢 , ship it! 🚢

[jaskarth]

Thanks for the testing @eme64, an thank you for the review @chhagedorn!

/integrate

[openjdk]

Going to push as commit 37d04a1.
Since your change was applied there have been 407 commits pushed to the master branch:

• 2c034f5: 8357146: ForkJoinPool:schedule(*) does not throw RejectedExecutionException when pool is shutdown
• bbceab0: 8352251: Implement JEP 518: JFR Cooperative Sampling
• e8eff4d: 8357530: C2 SuperWord: Diagnostic flag AutoVectorizationOverrideProfitability
• ... and 404 more: https://git.openjdk.org/jdk/compare/bd7c77898a75dece0586bef24d4e18d540f08288...master

Your commit was automatically rebased without conflicts.

[openjdk]

@jaskarth Pushed as commit 37d04a1.

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