8356275: TestCodeEntryAlignment fails with "Alignment must be <= CodeEntryAlignment"

[marc-chevalier]

In the original code, we have an align 32 here.

This alignment is pure optimization: we align the head of the loop to make the CPU happier. But if we set CodeEntryAlignment to 16, the 32 alignment makes an assert fail. Let's align to CodeEntryAlignment instead. It should be 32 by default, but if someone has a different opinion, it's still fine. Anyway, this alignment doesn't seem useful for correctness, so the consequences of an insufficient alignment are small. On the other hand, if someone wants to set CodeEntryAlignment to 64 for instance, it's also ok: 64-bit alignment is also a 32-bit alignment. We just lose a bit of space for no good reason but the user's input stating that we should prefer 64-bit alignment.

It seems questionable to me whether there is any sense in overriding the alignment when using such advanced features, that only exists on modern enough CPUs, so not with a 16-bit alignment, but for consistency, I suppose.

---

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Issue

• JDK-8356275: TestCodeEntryAlignment fails with "Alignment must be <= CodeEntryAlignment" (Bug - P3)

Reviewers

• Tobias Hartmann (@TobiHartmann - Reviewer)

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8356275: TestCodeEntryAlignment fails with "Alignment must be <= CodeEntryAlignment"

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At the time when this comment was updated there had been 33 new commits pushed to the master branch:

• 7dcc386: 8354024: [JMH] Create ephemeral UnixDomainSocketAddress provider with thread-safe close semantics
• 85db463: 8350203: [macos] Newlines and tabs are not ignored when drawing text to a Graphics2D object
• 38bb8ad: 8354941: Build failure with glibc 2.42 due to uabs() name collision
• ... and 30 more: https://git.openjdk.org/jdk/compare/de801fea76b1328f3bda503088618162388eb119...master

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[TobiHartmann]

Looks good and trivial to me.

[TobiHartmann]

The fixVersion in this issue is [26] but the fixVersion in .jcheck/conf is 25, a new backport will be created when this pr is integrated.)

Please make sure to set the fixVersion to 25 or tbd before integrating this.

[marc-chevalier]

Changed the Fix version to 25, and the warning seems to have been edited away. So I think it's good.

[marc-chevalier]

/integrate

Thanks @TobiHartmann review. And my first integrate as committer!

[openjdk]

Going to push as commit d930dc5.
Since your change was applied there have been 33 commits pushed to the master branch:

• 7dcc386: 8354024: [JMH] Create ephemeral UnixDomainSocketAddress provider with thread-safe close semantics
• 85db463: 8350203: [macos] Newlines and tabs are not ignored when drawing text to a Graphics2D object
• 38bb8ad: 8354941: Build failure with glibc 2.42 due to uabs() name collision
• ... and 30 more: https://git.openjdk.org/jdk/compare/de801fea76b1328f3bda503088618162388eb119...master

Your commit was automatically rebased without conflicts.

[openjdk]

@marc-chevalier Pushed as commit d930dc5.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

[dean-long]

Sorry for getting to this too late, but we also have the align32() function on x86 that would have worked for situations like this. See also JDK-8273459.