Hi,

I´ve installed Java 8 in RDuT OMVS and seeing big differences in performance compared with Java 7.1. Java 8 is roughly 2 times slower than 7.1. Does anybody having the same issue or is this just a configuration issue?

Thanks,

Bernd

Hi Bernd,

Are you using 64 bit or 31 bit java?  In addition what level of z/OS are you using?

Thanks,

Rick

Hi Rick,

I was trying both, 31 and 64 bit on a z/os V2.1.

Thanks,

Bernd

Hi Bernd,

Java 8 seems to have provided enhancements/changes that would allow the JVM to interact with the z
hardware differently then in previous versions of Java.  This could explain the performance
degradation if your environment is not tuned to use these features.

You may need to check the Java guides to determine if there are configurations that need to be changed
for your environment.

After doing some searching I was able to find some diagnostic information for JVM performance and how
to change the JVM to perform as previous releases:

    http://www-01.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.zos.80.doc/diag/problem_determination/optimizations_pd.html?lang=en

Let us know if this helps.

Thanks,

Rick

Hi Rick,

unfortunately this does not help. Any other ideas?

Thanks,

Bernd

Hi Bernd,

So the only other thing that I can think of is to perhaps check the configuration that you have against what's outlined in the configuration section of the z/OS User's Guide for IBM SDK, Java

http://www-01.ibm.com/support/knowledgecenter/SSYKE2_8.0.0/com.ibm.java.zos.80.doc/installing.html?lang=en

Also is your performance problems only happening with a single Java application or anything related to running Java.

Thanks,

Rick