I think it will be great if the IBM community contributed this kind of information to the Tomcat community.
Specifically there is an active issue discussion about this here:
I already commented myself. The more the merrier.
Thanks in advance,
Original Message:
Sent: 5/10/2023 4:52:00 PM
From: Joran Siu
Subject: RE: JDK 11 Temurin performance vs OpenJ9
I cannot make any definitive statements on Temurin performance -- I have limited experience, and the answer (as always) is "it depends" :) That said, the challenge with HotSpot on s390x for Java 8 and older releases is that lack of a JIT in the s390x port. A JIT implementation was contributed to the project for Java 9 [1], so performance is measurably better vs Java 8 HotSpot.
Semeru / Eclipse OpenJ9 benefits from decades of investment of z specific innovation into the JVM implementation. In terms of Tomcat performance, here's a dated OpenJ9 blog highlighting some of the benefits with Eclipse OpenJ9 JVM (measurements done on x86): https://blog.openj9.org/2019/11/20/tomcat-tradelite7-performance-of-openj9-with-default-shared-cache/
Besides the Z hardware exploitation / optimizations that James shared above, Semeru also sports optimizations for cloud deployments:
- Support for Class Data Sharing to accelerate startup : https://www.eclipse.org/openj9/docs/shrc/ Side note: Semeru container images trains itself with Tomcat to cache bootstrap classes for faster out-of-the-box startup! [2]
- JITServer capabilities : https://blog.openj9.org/2022/05/25/exploring-jitserver-on-the-new-linux-on-ibm-z16-platform
We also care very much about metrics like startup performance, time to first response, throughput and footprint: https://www.eclipse.org/openj9/performance/
I appreciate the challenge you've highlighted where open community packages may not provide Semeru based container images. Thanks Offer for chiming in on the Tomcat issue today -- it's users and advocates like yourself that can help us make inroads in broader adoption, so thank you!
- Joran
[1] https://openjdk.org/jeps/294
[2] https://github.com/ibmruntimes/semeru-containers/blob/ibm/17/jre/ubi/ubi9/Dockerfile.open.releases.full#L76-L97
Original Message:
Sent: Wed May 10, 2023 10:40 AM
From: Tomer Zelberzvig
Subject: JDK 11 Temurin performance vs OpenJ9
Thanks for the reply @James Tang
As Offer mentioned below it's really problematic that IBM works on a Java addition that the open community doesn't adopt.
Tomcat is of the examples but almost every s390x docker container is based on temurin and not Semeru.
Are there plans to share with other releases these acceleration/improvments?
Thanks!
Tomer Zelberzvig
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Tomer Zelberzvig
Original Message:
Sent: Mon May 08, 2023 10:47 AM
From: James Tang
Subject: JDK 11 Temurin performance vs OpenJ9
Hello Tomer,
Semeru runtimes with OpenJ9 JVM on zSystems (z/OS and Linux on Z) have specific performance improvement and acceleration that you would not see with Temurin. For example in z16,
https://community.ibm.com/community/user/ibmz-and-linuxone/blogs/james-tang1/2022/06/09/java-performance-on-ibm-z16
So, if you require these performance improvements, then it's strongly recommended to use the Semeru runtimes, downloadable here (select OS and s390x platform):
https://developer.ibm.com/languages/java/semeru-runtimes/downloads/
Thanks,
James
------------------------------
James Tang
Original Message:
Sent: Mon May 08, 2023 06:28 AM
From: Tomer Zelberzvig
Subject: JDK 11 Temurin performance vs OpenJ9
Hello,
I was wondering if anyone had any performance issues running JDK 11 Temurin.
In the past, I've used OpenJDK 8 which had some performance issues running on Z which made me switch to OpenJ9.
Was wondering if there are still known issues around that area?
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Tomer Zelberzvig
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