Strage jmap heap output for G1 on 32bit JVM

Jakub Kubryński jk at codearte.io
Fri May 15 15:22:14 UTC 2015


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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