Strage jmap heap output for G1 on 32bit JVM
jesper.wilhelmsson at oracle.com
Wed May 20 15:48:51 UTC 2015
FYI, I filed JDK-8080784 to cover this issue.
Jakub Kubryński skrev den 20/5/15 16:50:
> Yes, I'll check it on latest Jdk9 and let you know.
> 20 maj 2015 16:35 "Jesper Wilhelmsson" <jesper.wilhelmsson at oracle.com
> <mailto:jesper.wilhelmsson at oracle.com>> napisał(a):
> Ok. I tried that as well but it didn't reproduce.
> After a closer look it seems as if it is the number of regions that is wrong
> and causes the huge free size reported. There have been a few changes in
> this area recently which may have fixed this issue.
> Is it possible to try your reproducer with a recent build of JDK 9 or the
> latest version of 8u from the OpenJDK source repositories?
> Jakub Kubryński skrev den 20/5/15 15:23:
> 64 bit Linux with 32bit JVM.
> 20 maj 2015 15:18 "Jesper Wilhelmsson" <jesper.wilhelmsson at oracle.com
> <mailto:jesper.wilhelmsson at oracle.com>
> <mailto:jesper.wilhelmsson at oracle.com
> <mailto:jesper.wilhelmsson at oracle.com>>> napisał(a):
> 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.
> Jakub Kubryński skrev den 15/5/15 17:22:
> I've just checked that on 32bit JVM (HotSpot 8u45) jmap reports
> information for G1 collector. As you can see Xmx is set to 2G
> (which fits
> MaxHeapSize) but regions count (almost 15k) and capacity is
> Any ideas
> Heap Configuration:
> MinHeapFreeRatio = 40
> MaxHeapFreeRatio = 70
> MaxHeapSize = 2147483648 <tel:2147483648>
> <tel:2147483648 <tel: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 <tel:15032385536> <tel:15032385536
> <tel:15032385536>> (14336.0MB)
> used = 76347888 (72.81101989746094MB)
> free = 14956037648 (14263.188980102539MB)
> 0.5078893687043872% used
> Best regards,
> Jakub Kubrynski
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