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  1. JDK
  2. JDK-8270100

Fix some inaccurate GC logging

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 18
    • Component/s: hotspot
    • Labels:
      None
    • Subcomponent:
      gc
    • Resolved In Build:
      b07
    • CPU:
      generic
    • OS:
      generic

      Description

      If running with -Xlog:gc+heap*=trace the JVM will print the extra per thread amount which is added to the new generation on resize:

      [0,105s][debug][gc,ergo,heap ] GC(0) New generation size 34112K->34176K [eden=27392K,survivor=3392K]
      [0,105s][trace][gc,ergo,heap ] GC(0) [allowed 0K extra for 0 threads]

      Currently this will always print "0K extra for 0 threads" no matter how much extra space was added.

      Also, the shrink factor will always be printed to be 0%, even if we run with -XX:-ShrinkHeapInSteps which pins the shrink factor at 100%:

      [13,213s][trace][gc,heap ] GC(34) shrink_bytes: 463564,0K current_shrink_factor: 0 new shrink factor: 0 _min_heap_delta_bytes: 192,0K
      [13,239s][trace][gc,heap ] GC(34) Shrinking tenured generation from 531852K to 68288K

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              Assignee:
              simonis Volker Simonis
              Reporter:
              simonis Volker Simonis
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                Dates

                Created:
                Updated:
                Resolved: