JDK-6984368 : Large default heap size does not allow to use zero based compressed oops.
  • Type: Bug
  • Component: hotspot
  • Sub-Component: compiler
  • Affected Version: hs19
  • Priority: P4
  • Status: Closed
  • Resolution: Fixed
  • OS: solaris_10
  • CPU: sparc
  • Submitted: 2010-09-13
  • Updated: 2011-03-08
  • Resolved: 2011-03-08
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JDK 6 JDK 7 Other
6u21pFixed 7Fixed hs19Fixed
Related Reports
Relates :  
JDK-6999491 - non-zero COOPs are used when they should not
Description
For 64 bit VM the default heap size is set to 1/4 of available physical memory. With memory > 120Gb the default heap size would be set to about 30Gb when compressed oops are used. It is fine for regular compressed oops but a little big for zero based compressed oops since lower part of virtual memory is used by os.
Comments
EVALUATION http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/a8b66e00933b
09-10-2010
EVALUATION http://hg.openjdk.java.net/hsx/hsx19/baseline/rev/4cf84525dc4d
08-10-2010
EVALUATION http://hg.openjdk.java.net/jdk7/hotspot-rt/hotspot/rev/a8b66e00933b
28-09-2010
PUBLIC COMMENTS The heap size expression in max_heap_for_compressed_oops() does not take into account HeapBaseMinAddress value which is used to get zero based compressed oops. Also MaxPermSize is rounded up in CollectorPolicy::initialize_flags() which makes invalid all expressions which use it before rounding.
15-09-2010
EVALUATION http://hg.openjdk.java.net/jdk7/hotspot-comp/hotspot/rev/a8b66e00933b
15-09-2010
EVALUATION The heap size expression in max_heap_for_compressed_oops() does not take into account HeapBaseMinAddress value used for zero based compressed oops.
13-09-2010