IV68281: INCORRECT DURATION/INTERVAL VERBOSE GC TIMES

APAR status

• Closed as program error.

Error description

• Error Message: Times appear to be inflated close to 2xInter-GC
  intervals:<exclusive-start id="50"
  timestamp="2014-11-20T18:14:15.395"
  intervalms="830.817"><exclusive-start id="62"
  timestamp="2014-11-20T18:14:15.640"
  intervalms="477.967">According to timestamps it should be 640 -
  395 = 245ms, but reported as ?478ms.GC duration:<exclusive-start
  id="74" timestamp="2014-11-20T18:14:16.609"
  intervalms="1893.006"><exclusive-end id="85"
  timestamp="2014-11-20T18:14:16.948" durationms="661.689"
  />Duration as per timestamps should be 948 - 609 = 339ms, but
  reported as ?662ms.
  .
  Stack Trace: N/A
  .
  

Local fix

• No workaround.
  

Problem summary

• Rounding errors in microsecond times calculations on Windows
  64-bit cause inaccurate times in verbose GC log.
  

Problem conclusion

• Use floating-point calculations to calculate time delta.
  .
  This APAR will be fixed in the following Java Releases:
     7    SR8 FP10  (7.0.8.10)
     6 R1 SR8 FP3   (6.1.8.3)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the 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

• R260 PSY

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