8373781: [CRaC] Permit -XX:CPUFeatures on other platforms

[rvansa]

Currently -XX:CPUFeatures option is available only on x86_64. This complicates creating multiarch container images that are meant to be universally runnable (with -XX:CPUFeatures=generic).

I propose to make this option available on all architectures, with the non-arch specific values:

• generic
• native
• ignore

The implementation on non-x86_64 will only validate the sanity of the value.

The related option -XX:+ShowCPUFeatures will print an informative message (saying that the option does not make much sense).

-XX:+IgnoreCPUFeatures will be permitted as well, but it will be a no-op on the other architectures.

---

Progress

• Change must not contain extraneous whitespace

Issue

• JDK-8373781: [CRaC] Permit -XX:CPUFeatures on other platforms (Enhancement - P4)

Reviewers

• Timofei Pushkin (@TimPushkin - Committer)

Reviewing

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

[openjdk]

@rvansa 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:

8373781: [CRaC] Permit -XX:CPUFeatures on other platforms

Reviewed-by: tpushkin

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At the time when this comment was updated there had been 3 new commits pushed to the crac branch:

• 15dcf3b: 8373687: [CRaC] Add metrics through jcmd
• 6fa1e41: 8373043: [CRaC] remove CPUFeatures qemu-kvm test
• 311dafd: 8373027: [CRaC] [CRIU] x86: FPU xsave area present, but host cpu doesn't support it

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Webrevs

• 04: Full - Incremental (0bab0747)
• 03: Full - Incremental (e4849639)
• 02: Full - Incremental (a58eee1e)
• 01: Full - Incremental (2a0aecd1)
• 00: Full (1e92e5ec)

[TimPushkin]

Implementation LGTM, but we have non-x86 machines in CI so it makes sense to add a test for this

[rvansa]

I've replaced the shell-based CPUFeatures test, and added test cases.

[rvansa]

@TimPushkin The tests now pass on all platforms but Mac + x64, where we need to backport upstream changes after GH obsoleted a base image. Please re-review.

[TimPushkin]

Just two minor things, since you are planning a follow-up maybe it'll be easier/faster to fix them there

[TimPushkin]

I'd prefer to have either #endif // LINUX or #endif // !LINUX — there is a lot of ifdef-s around so it's a bit harder to read without such comments

[TimPushkin]

Suggested change

	* Copyright (c) 2023,2025, Azul Systems, Inc. All rights reserved.
	* Copyright (c) 2023, 2025, Azul Systems, Inc. All rights reserved.

[rvansa]

/integrate

[openjdk]

Going to push as commit abf0868.
Since your change was applied there have been 3 commits pushed to the crac branch:

• 15dcf3b: 8373687: [CRaC] Add metrics through jcmd
• 6fa1e41: 8373043: [CRaC] remove CPUFeatures qemu-kvm test
• 311dafd: 8373027: [CRaC] [CRIU] x86: FPU xsave area present, but host cpu doesn't support it

Your commit was automatically rebased without conflicts.

[openjdk]

@rvansa Pushed as commit abf0868.

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