Different result presented in os.arch between openjdk and openj9 on Mac

[kiszk]

I realized that os.arch is different between openjdk and openj9 on Mac. On Linux, they return the same os.arch.

$ /Library/Java/JavaVirtualMachines/jdk1.8.0_181.jdk/Contents/Home/bin/java -XshowSettings:all
...
    os.arch = x86_64
...
$ /Library/Java/JavaVirtualMachines/adoptopenjdk-8-openj9.jdk/Contents/Home/bin/java -XshowSettings:all
...
    os.arch = amd64
...

This difference causes an JNI link error in Spark. This is because zstd-jni determines dll path by using os.arch as a part of the path name.

[keithc-ca]

This seems to be platform specific: on a Linux x86 system:

$ ./bin/java -version
openjdk version "1.8.0_202"
OpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_202-b08)
OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.202-b08, mixed mode)
$ ./bin/java -XshowSettings:properties |& grep os.arch
    os.arch = amd64

It's surprising to me that hotspot would use a different name on MacOSX for the same CPU architecture.

[kiszk]

Yes, this problem occurs only on Mac.

This code seems to try to follow the behavior of OpenJDK. I am investigating why it does not work.

[DanHeidinga]

Property is set in https://github.com/eclipse/openj9/blob/f0820b5ca51197ee3e58925920cdfc9fe5dc5220/runtime/vm/vmprops.c#L778-L782

[DanHeidinga]

Which is set in OMR:
https://github.com/eclipse/omr/blob/5edfbe1a6e36d6b462283b2aaee16147cb570c52/port/unix/omrsysinfo.c#L524-L525

and we define J9HAMMER for OSX:
https://github.com/eclipse/omr/blob/5edfbe1a6e36d6b462283b2aaee16147cb570c52/omrmakefiles/rules.osx.mk#L27

[DanHeidinga]

To fix this we either need to

1. update j9sysinfo_get_CPU_architecture / omrsysinfo_get_CPU_architecture to return x86_64 and check all the callers are ready to deal with this string, or
2. change vmprops.c to map from amd64 to x86_64 on osx.

[kiszk]

Thank you for your investigation and comments.
IMHO, 2. is preferable to me.

[pshipton]

@keithc-ca can you please open a PR to fix this for the 0.14.2 release.

[keithc-ca]

can you please open a PR to fix this for the 0.14.2 release

Done, see #5771.