IJ02225: OPERATINGSYSTEMMXBEAN: GETPROCESSCPULOAD() AND GETPROCESSCPUTIMEBYNS() RETURN INCORRECT RESULTS

APAR status

• Closed as program error.

Error description

• Error Message: N/A
  .
  Stack Trace: N/A
  .
  OperatingSystemMXBean.getProcessCpuLoad() and
  OperatingSystemMXBean.getProcessCpuTimeByNS() return incorrect
  results.
  

Local fix

• Setting system property
  "com.ibm.lang.management.OperatingSystemMXBean.isCpuTime100ns"
  to "true" fixes this issue.
  

Problem summary

• OperatingSystemMXBean.getProcessCpuLoad() and
  OperatingSystemMXBean.getProcessCpuTimeByNS() return incorrect
  values which are scaled by a factor of 100.
  

Problem conclusion

• OperatingSystemMXBean.getProcessCpuLoad() and
  OperatingSystemMXBean.getProcessCpuTimeByNS() are dependent upon
  OperatingSystemMXBean.getProcessCpuTime(). Recently, the API
  definition of OperatingSystemMXBean.getProcessCpuTime() changed.
  Before, it returned CPU time in 100 nanosecond units. Now, it
  returns CPU time in nanoseconds by default but it can also
  return CPU time in 100 nanosecond units when the system property
  "com.ibm.lang.management.OperatingSystemMXBean.isCpuTime100ns"
  is to set "true". The implementation of
  OperatingSystemMXBean.getProcessCpuLoad() and
  OperatingSystemMXBean.getProcessCpuTimeByNS() has been updated
  to account for the change in the API definition of
  OperatingSystemMXBean.getProcessCpuTime().
  .
  This APAR will be fixed in the following Java Releases:
     8    SR5 FP5   (8.0.5.5)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  Service Refreshes and Fix Packs can be found at:
             https://www.ibm.com/developerworks/java/jdk/
  

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

• R270 PSY

     UP