IJ50196: INCREASED CPU USAGE WHEN INVOKING JAVA INVOCATION APIS

APAR status

• Closed as program error.

Error description

• Error Message: Increased CPU usage and file I/O observed when
  invoking Java Invocation APIs from 31-bit native
              code to 64-bit Java Virtual Machines on z/OS.
  .
  Stack Trace: N/A
  .
  This issue is observed on z/OS only for 31-bit native code
  invoking 64-bit Java Virtual Machines
              functions.
  

Local fix

• Recompile the native libraries to 64-bit, if possible.
  

Problem summary

• On each invocation of the following APIs, the 31-bit libjvm31
  wrapper library will re-query the target function
          pointer, which results in additional DLL load and query
  operations.
         - AttachCurrentThread
         - AttachCurrentThreadAsDaemon
         - DestroyJavaVM
         - DetachCurrentThread
         - GetEnv
         - GetStringPlatform
         - GetStringPlatformLength
         - NewStringPlatform
  

Problem conclusion

• The libjvm31 wrapper library has been updated to cache the
  target function descriptors.
  
  .
  This APAR will be fixed in the following Releases:
  .
  IBM Semeru Runtimes
     11              11.0.23.0
     17              17.0.11.0
  IBM SDK, Java Technology Edition
     8    SR8 FP25  (8.0.8.25)
  .
  Downloads and supplementary documentation can be found at the
  following locations:
  - For non z/OS operating systems:
    - IBM Semeru Runtimes, Version 11 and later
      https://www.ibm.com/semeru-runtimes/downloads/
    - IBM SDK, Java Technology Edition, Version 8
      https://www.ibm.com/support/pages/java-sdk-downloads/
  - For the z/OS operating system:
    - Java SDK Products on z/OS
      https://www.ibm.com/support/pages/java-sdk-products-zos
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  J9 COMMON CODE

• Fixed component ID

  620700127

Applicable component levels