Strage jmap heap output for G1 on 32bit JVM

Jesper Wilhelmsson jesper.wilhelmsson at oracle.com
Wed May 20 13:18:37 UTC 2015


Hi,

Does this reproduce every time?
What platform is it?

I have tried to reproduce this on 32bit linux but can't see anything weird 
there. It seems likely that there is a variable with the wrong type somewhere on 
the way. I'll see if I can find something.
/Jesper


Jakub Kubryński skrev den 15/5/15 17:22:
> Hi,
>
> I've just checked that on 32bit JVM (HotSpot 8u45) jmap reports strange region
> information for G1 collector. As you can see Xmx is set to 2G (which fits
> MaxHeapSize) but regions count (almost 15k) and capacity is incorrect. Any ideas
> why?
>
> Heap Configuration:
>     MinHeapFreeRatio         = 40
>     MaxHeapFreeRatio         = 70
>     MaxHeapSize              = 2147483648 (2048.0MB)
>     NewSize                  = 1048576 (1.0MB)
>     MaxNewSize               = 428867584 (409.0MB)
>     OldSize                  = 4194304 (4.0MB)
>     NewRatio                 = 2
>     SurvivorRatio            = 8
>     MetaspaceSize            = 16777216 (16.0MB)
>     CompressedClassSpaceSize = 1073741824 (1024.0MB)
>     MaxMetaspaceSize         = 4294963200 (4095.99609375MB)
>     G1HeapRegionSize         = 1048576 (1.0MB)
>
> Heap Usage:
> G1 Heap:
>     regions  = 14336
>     capacity = 15032385536 (14336.0MB)
>     used     = 76347888 (72.81101989746094MB)
>     free     = 14956037648 (14263.188980102539MB)
>     0.5078893687043872% used
>
> --
> Best regards,
> Jakub Kubrynski


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