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Merged
TheRealMDoerr merged 3 commits into from
Dec 12, 2025
Merged

SapMachine #2137: Linux: We should use transparent huge pages in some configurations #2138

TheRealMDoerr merged 3 commits into from
Dec 12, 2025
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@TheRealMDoerr TheRealMDoerr commented Dec 10, 2025 •
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Enable UseTransparentHugePages by default if the machine and JVM configuration are suited for their usage. Some tests need a small adaptation to support that.

fixes #2137

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SapMachine commented Dec 10, 2025

Hello @TheRealMDoerr, this pull request fulfills all formal requirements.

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SapMachine commented Dec 10, 2025

Hello @TheRealMDoerr, this pull request fulfills all formal requirements.

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RealCLanger commented Dec 11, 2025

I think this looks good but I'm wondering whether it's possible to do the changes to the tests in OpenJDK? It should not be wrong there, no?

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dbriemann approved these changes Dec 11, 2025
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TheRealMDoerr commented Dec 11, 2025

I think this looks good but I'm wondering whether it's possible to do the changes to the tests in OpenJDK? It should not be wrong there, no?

I would like to have them in OpenJDK because they do no harm. However, I don't have any justification for such changes without changing the default of UseTransparentHugePages. Note that these tests use @requires vm.flagless.

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MBaesken commented Dec 11, 2025 •
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java.md mentions UseTransparentHugePages

https://github.com/openjdk/jdk/blob/692edc4879489d44a477a03028eb3e7ef9dff388/src/java.base/share/man/java.md?plain=1#L1579

Seems what is said is not true now any more for SapMachine; not sure how important it is but might be better to adjust (of course in SapMachine) ?

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SapMachine commented Dec 11, 2025

Hello @TheRealMDoerr, this pull request fulfills all formal requirements.

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RealCLanger commented Dec 12, 2025

I think this looks good but I'm wondering whether it's possible to do the changes to the tests in OpenJDK? It should not be wrong there, no?

I would like to have them in OpenJDK because they do no harm. However, I don't have any justification for such changes without changing the default of UseTransparentHugePages. Note that these tests use @requires vm.flagless.

Yes, I see your point, it's hard to motivate in OpenJDK, I guess.

@TheRealMDoerr TheRealMDoerr merged commit aece2fb into sapmachine Dec 12, 2025
139 of 142 checks passed
@TheRealMDoerr TheRealMDoerr deleted the 2137_TransparentHugePages branch December 12, 2025 14:16
TheRealMDoerr added a commit that referenced this pull request Dec 12, 2025
@TheRealMDoerr
SapMachine (26) #2137: Linux: We should use transparent huge pages in…
57af063 
… some configurations (#2138)
@TheRealMDoerr TheRealMDoerr mentioned this pull request Dec 12, 2025
Merged
TheRealMDoerr added a commit that referenced this pull request Dec 16, 2025
@TheRealMDoerr
SapMachine #2137: Linux: We should use transparent huge pages in some…
621f2c6 
… configurations (#2138)

Linux: Enable UseTransparentHugePages if
- UseLargePages and UseTransparentHugePages are not set explicitly
- transparent huge pages are supported by the system configuration and the huge pages size is not above 2MB
- UseZGC or UseShenandoahGC are not selected
- the Java Heap is not set to 128MB or lower
@TheRealMDoerr TheRealMDoerr mentioned this pull request Dec 16, 2025
Merged
TheRealMDoerr added a commit that referenced this pull request Dec 17, 2025
@TheRealMDoerr
SapMachine #2137: Linux: We should use transparent huge pages in some…
cca2fc3 
… configurations (#2138)

Linux: Enable UseTransparentHugePages if
- UseLargePages and UseTransparentHugePages are not set explicitly
- transparent huge pages are supported by the system configuration and the huge pages size is not above 2MB
- UseZGC or UseShenandoahGC are not selected
- the Java Heap is not set to 128MB or lower
TheRealMDoerr added a commit that referenced this pull request Dec 17, 2025
@TheRealMDoerr
SapMachine #2137: Linux: We should use transparent huge pages in some…
06b48eb 
… configurations (#2138)

Linux: Enable UseTransparentHugePages if
- UseLargePages and UseTransparentHugePages are not set explicitly
- transparent huge pages are supported by the system configuration and the huge pages size is not above 2MB
- UseZGC or UseShenandoahGC are not selected
- the Java Heap is not set to 128MB or lower
TheRealMDoerr added a commit that referenced this pull request Dec 17, 2025
@TheRealMDoerr
SapMachine #2137: Linux: We should use transparent huge pages in some…
31da624 
… configurations (#2138)

Linux: Enable UseTransparentHugePages if
- UseLargePages and UseTransparentHugePages are not set explicitly
- transparent huge pages are supported by the system configuration and the huge pages size is not above 2MB
- UseZGC or UseShenandoahGC are not selected
- the Java Heap is not set to 128MB or lower
TheRealMDoerr added a commit that referenced this pull request Dec 18, 2025
@TheRealMDoerr
SapMachine (26) #2137: Linux: We should use transparent huge pages in…
f0a13ea 
… some configurations (#2138)

Linux: Enable UseTransparentHugePages if
- UseLargePages and UseTransparentHugePages are not set explicitly
- transparent huge pages are supported by the system configuration and the huge pages size is not above 2MB
- UseZGC or UseShenandoahGC are not selected
- the Java Heap is not set to 128MB or lower
RealCLanger pushed a commit that referenced this pull request Dec 18, 2025
@TheRealMDoerr @RealCLanger
SapMachine #2137: Linux: We should use transparent huge pages in some…
2db0c7c 
… configurations (#2138)

Linux: Enable UseTransparentHugePages if
- UseLargePages and UseTransparentHugePages are not set explicitly
- transparent huge pages are supported by the system configuration and the huge pages size is not above 2MB
- UseZGC or UseShenandoahGC are not selected
- the Java Heap is not set to 128MB or lower
RealCLanger pushed a commit that referenced this pull request Dec 18, 2025
@TheRealMDoerr @RealCLanger
SapMachine #2137: Linux: We should use transparent huge pages in some…
4fd5a5a 
… configurations (#2138)

Linux: Enable UseTransparentHugePages if
- UseLargePages and UseTransparentHugePages are not set explicitly
- transparent huge pages are supported by the system configuration and the huge pages size is not above 2MB
- UseZGC or UseShenandoahGC are not selected
- the Java Heap is not set to 128MB or lower
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@dbriemann dbriemann dbriemann approved these changes

@MBaesken MBaesken MBaesken approved these changes

@RealCLanger RealCLanger RealCLanger approved these changes

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Linux: We should use transparent huge pages in some configurations

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