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Bug ID: JDK-7017008 G1: Turn on compressed oops by default.
JDK-7017008 : G1: Turn on compressed oops by default.

Details
Type:
Enhancement
Submit Date:
2011-02-03
Status:
Closed
Updated Date:
2011-03-08
Project Name:
JDK
Resolved Date:
2011-03-08
Component:
hotspot
OS:
generic
Sub-Component:
gc
CPU:
generic
Priority:
P4
Resolution:
Fixed
Affected Versions:
7
Fixed Versions:
hs21 (b03)

Related Reports
Backport:

Sub Tasks

Description
Whne the maximum heap size allows compressed oops to be turned on, the following code in arguments.cpp:

#ifdef _LP64
  // Check that UseCompressedOops can be set with the max heap size allocated
  // by ergonomics.
  if (MaxHeapSize <= max_heap_for_compressed_oops()) {
#if !defined(COMPILER1) || defined(TIERED)
    if (FLAG_IS_DEFAULT(UseCompressedOops) && !UseG1GC) {
      FLAG_SET_ERGO(bool, UseCompressedOops, true);
    }
#endif

turns off compressed oops when G1 is enabled.

This is incorrect.

                                    

Comments
SUGGESTED FIX

Remove workaround from arguments.cpp.
Re-enable GCBasher/G1 tests on 64 bit windows.
                                     
2011-02-09
EVALUATION

A workaround in the ergo code prohibits turning on compressed oops (when it could be) when G1 is enabled.
                                     
2011-02-09
EVALUATION

http://hg.openjdk.java.net/jdk7/hotspot-gc/hotspot/rev/59e20a452a2a
                                     
2011-02-09



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