Add RISC-V 64 Support

[Avimitin]

Is your feature request related to a problem? Please describe.
I am trying to build this program on RISC-V 64 Arch Linux platform. And I found that it currently only support x86_64 and i386. I wonder if there are any x86_64 specific code? Or it can just be built without code modification?

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[macrakis]

Thanks for your interest in running OpenSearch on RISC-V. Although RISC-V is not explicitly a supported platform, OpenSearch should build and run correctly on any JVM platform, except for a small amount of functionality that depends on native x86 code, notably KNN.

I suggest you go ahead, build it, and try it out. I will close this issue report, but if you run into difficulties, please provide a detailed problem report including version numbers of your JVM and OS.

[anasalkouz]

Closing this for now. @Avimitin, please feel free to reopen if you faced any issues during the build

[Avimitin]

Context: building on Linux 5.16.11-arch1-1 (riscv64) QEMU environment, for opensearch version 1.2.4, using java-11-openjdk, gradle 6.6.1.

---

I actually got problem when building the opensearch. During the build, it reports that can not determine architecture from [riscv64], this error is from Script '/build/opensearch/src/OpenSearch-1.2.4/gradle/runtime-jdk-provision.gradle' line: 33.

I tried to add this line to return the proper system architecture:

--- buildSrc/src/main/java/org/opensearch/gradle/Architecture.java
+++ buildSrc/src/main/java/org/opensearch/gradle/Architecture.java
@@ -40,6 +40,7 @@
     public static Architecture current() {
         final String architecture = System.getProperty("os.arch", "");
         switch (architecture) {
+            case "riscv64":
             case "amd64":
             case "x86_64":
                 return X64;

And I found this error in the new build:

* What went wrong:
Execution failed for task ':plugins:analysis-icu:test'.
> A problem occurred starting process 'command '/build/.gradle/caches/transforms-2/files-2.1/8e4cc3c6a9f53237ac703baa5e202c9b/linux-15.0.1-x64.tar.gz/bin/java''

Is the opensearch trying to download a java executable for current architecture? Is there a build argument to close this behavior and let it choose a executable from target machine?

[dblock]

Let's reopen this now that we have a clear bug.

I don't have an answer to your question @Avimitin, but add comments to the issue as you make progress!

[dbwiddis]

Hi @Avimitin. Not sure if you've made any more progress on this. I spent the last few days looking into this. I was of course able to reproduce the initial failure in the Architecture class but after adding the riscv64 entry as you did, have not been able to reproduce the later error. After making the same architecture change, I was successfully able to build on a GNU Compile Farm RISC-V 64 machine (gcc92).

This report looks identical to the symptoms in #1303 (for a different architecture) which includes some stack traces. The stack traces do not have any OpenSearch code in them; they are entirely Gradle internal code, and share the same Gradle version as you have here, 6.6.1.

The stack trace seems to imply the problem is in Gradle's determining of the appropriate runtime Java version. One of the lines in the stack trace is:

at org.gradle.api.tasks.testing.Test.getJavaVersion(Test.java:266)

This particular line of code was changed in Gradle 6.7.0, in gradle/gradle#14031 which may or may not have any effect on fixing it.

I do think there's a strong possibility that this bug in OpenJ9 may be the root cause of both your issue and #1303, since they share the commonality of non-Hotspot JVMs: eclipse-openj9/openj9#11013

Bottom line:

• I believe the test failures are associated with a bug in either Gradle or OpenJ9 and may be fixed by using newer versions.
• Please submit a PR to add the riscv64 option per your change noted above. There's an open PR Add ppc64le architecture #3435 for a similar change on ppc64.