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  1. JDK
  2. JDK-4618940

Repetitive Full Garbage Collections occuring with -Xincgc

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    Details

    • Subcomponent:
      gc
    • Resolved In Build:
      01
    • CPU:
      x86, sparc
    • OS:
      solaris_8, windows_nt

      Backports

        Description

        The customer is seeing their application go into long bouts of Full GCs, bringing their large application to a standstill. They have now been able to provide a testcase, and demonstration settings and output from a debug jvm (attached). Here's the end a Test output:

        loop 55 39976960 166784 39810176
        [Full GC 40776K->19469K(20160K), 0.2886160 secs]
        [Full GC 19981K->19469K(19712K), 5.8652228 secs]
        loop 56 27197440 122216 27075224
        loop 57 36831232 147968 36683264
        [Full GC 40776K->19469K(20160K), 0.2903560 secs]
        [Full GC 19981K->19469K(19712K), 0.2947036 secs]
        loop 58 24117248 168936 23948312
        loop 59 33685504 129192 33556312
        [Full GC 40776K->19469K(20160K), 0.2875250 secs]
        [Full GC 19981K->19469K(19712K), 0.2930166 secs]
        loop 60 20971520 150120 20821400
        loop 61 30605312 175848 30429464
        loop 62 40173568 136128 40037440
        [Full GC 40776K->19469K(20160K), 0.2924913 secs]
        [Full GC 19981K->19469K(19712K), 0.2949892 secs]
        loop 63 27459584 157032 27302552
        loop 64 37093376 182784 36910592
        [Full GC 40776K->19469K(20160K), 0.2890132 secs]
        [Full GC 19981K->19469K(19712K), 0.2955358 secs]
        loop 65 24313856 138216 24175640
        loop 66 33947648 163968 33783680
        [Full GC 40776K->19469K(20160K), 0.2897438 secs]
        [Full GC 19981K->19469K(19712K), 0.2984033 secs]
        loop 67 21168128 119400 21048728
        loop 68 30801920 145152 30656768
        loop 69 40435712 170944 40264768
        [Full GC 40776K->19469K(20160K), 0.2919497 secs]
        [Full GC 19981K->19469K(19712K), 0.2915988 secs]

        In their actual application, they've seen Full GC's take nearly a minute, freeing 300M each time. They go on to say:

          I've been playing about with a bit more. Running with jdk1.4.0-beta3,
          I find that, as I increase the first parameter, the behaviour switches
          from good to bad at this point:

          C:\jdk1.4.0-beta3\bin\java.exe -mx40M -Xincgc -verbose:gc -classpath
          C:\projects\ideatest Test 2391840 50000 50

          i.e. 2391800 is fine 2391840 collapses into continual gcs.





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                Assignee:
                jloizeausunw Jane Loizeaux (Inactive)
                Reporter:
                mbowyer Mark Bowyer (Inactive)
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