Performance notes for 0.29

[pshipton]

@vijaysun-omr @mpirvu @0xdaryl are there performance highlights we should list for 0.29.0? Something to replace the 0.27.0 highlights that were at https://www.eclipse.org/openj9/news which I've copied below. For the moment we're removing the obsolete notes via https://github.com/eclipse-openj9/openj9-website/pull/298

Other performance highlights

-   The performance of method invocation via reflection is improved by reducing stack walking overhead related to access checking associated with that API.
-   The JIT compiler includes several incremental throughput improvements related to the warm hotness level and loop handling.
-   On AArch64, the JIT compiler provides incremental performance improvements for applications generally, including: reducing Java synchronization overhead, improving array access performance in loops, and increased virtual and JNI method dispatch performance.
-   New POWER10 hardware features are exploited to improve application path length and the performance of various array and byte operations.

[vijaysun-omr]

We could mention the fact that JIT server GAed and AArch64 performance got even better. I also feel that some of the GC team's work could be mentioned (may need to ask Aleks or Dmitri on what was delivered when exactly). There were improvements done for the various JEPs, like vector, value types etc. too but given that those are incubator JEPs, I wonder if we should be mentioning them.

[pshipton]

@amicic @dmitripivkine are there any performance highlights added in the 0.29 release? @tajila fyi as well.

For everyone's reference, the release notes are https://www.eclipse.org/openj9/docs/version0.29/

[0xdaryl]

For 0.29, AArch64 became a production release for JDK 8 and 11. To achieve that required a continuous improvement in performance prior to release. I know, not particularly specific, but the final push between 0.27 and 0.29 I believe only amounted to smaller improvements.

[pshipton]

So we are ready for the January 0.30 release, I've also created https://github.com/eclipse-openj9/openj9-website/issues/300 to hold comments. Pls add your input for 0.30 there.

Release notes to date for 0.30 are https://eclipse-openj9.github.io/openj9-docs/version0.30/

[mpirvu]

We could mention the fact that JIT server GAed

There is already a message of this sort in the Release Notes for 0.29.0. I am not sure we want to repeat the same sentence on the Performance Notes, especially that performance hasn't improved that much since the previous release.

[0xdaryl]

In 0.29:

• AArch64 implemented significant performance improvements to System.arraycopy() and interface method dispatches from JIT-compiled methods.

[zl-wang]

In 0.29/0.30: 1) Partial optimization of JEP#338 (Vector API) is delivered; 2) 14% better write-barrier sequence on Power was delivered; 3) 15-30% better String.indexOf (on Power10 specifically) was delivered;

[pshipton]

@zl-wang is anything in the previous comment specific to 0.29? Otherwise I'll add this information when 0.30 is released.