src/share/vm/runtime/arguments.cpp

*** 1081,1111 ****
      }
      FLAG_SET_DEFAULT(UseAdaptiveSizePolicy, false);
    }
  }
  
- // If the user has chosen ParallelGCThreads > 0, we set UseParNewGC
- // if it's not explictly set or unset. If the user has chosen
- // UseParNewGC and not explicitly set ParallelGCThreads we
- // set it, unless this is a single cpu machine.
  void Arguments::set_parnew_gc_flags() {
    assert(!UseSerialGC && !UseParallelOldGC && !UseParallelGC && !UseG1GC,
           "control point invariant");
    assert(UseParNewGC, "Error");
  
    // Turn off AdaptiveSizePolicy for parnew until it is complete.
    disable_adaptive_size_policy("UseParNewGC");
  
!   if (ParallelGCThreads == 0) {
!     FLAG_SET_DEFAULT(ParallelGCThreads,
!                      Abstract_VM_Version::parallel_worker_threads());
!     if (ParallelGCThreads == 1) {
!       FLAG_SET_DEFAULT(UseParNewGC, false);
!       FLAG_SET_DEFAULT(ParallelGCThreads, 0);
!     }
    }
!   if (UseParNewGC) {
      // By default YoungPLABSize and OldPLABSize are set to 4096 and 1024 respectively,
      // these settings are default for Parallel Scavenger. For ParNew+Tenured configuration
      // we set them to 1024 and 1024.
      // See CR 6362902.
      if (FLAG_IS_DEFAULT(YoungPLABSize)) {
--- 1081,1107 ----
      }
      FLAG_SET_DEFAULT(UseAdaptiveSizePolicy, false);
    }
  }
  
  void Arguments::set_parnew_gc_flags() {
    assert(!UseSerialGC && !UseParallelOldGC && !UseParallelGC && !UseG1GC,
           "control point invariant");
    assert(UseParNewGC, "Error");
  
    // Turn off AdaptiveSizePolicy for parnew until it is complete.
    disable_adaptive_size_policy("UseParNewGC");
  
!   if (FLAG_IS_DEFAULT(ParallelGCThreads)) {
!     FLAG_SET_DEFAULT(ParallelGCThreads, Abstract_VM_Version::parallel_worker_threads());
!     assert(ParallelGCThreads > 0, "We should always have at least one thread by default");
!   } else if (ParallelGCThreads == 0) {
!     jio_fprintf(defaultStream::error_stream(),
!         "The ParNew GC can not be combined with -XX:ParallelGCThreads=0\n");
!     vm_exit(1);
    }
! 
    // By default YoungPLABSize and OldPLABSize are set to 4096 and 1024 respectively,
    // these settings are default for Parallel Scavenger. For ParNew+Tenured configuration
    // we set them to 1024 and 1024.
    // See CR 6362902.
    if (FLAG_IS_DEFAULT(YoungPLABSize)) {
*** 1128,1138 ****
          warning("Forcing +ParGCUseLocalOverflow: needed if using compressed references");
        }
        FLAG_SET_DEFAULT(ParGCUseLocalOverflow, true);
      }
      assert(ParGCUseLocalOverflow || !UseCompressedOops, "Error");
-   }
  }
  
  // Adjust some sizes to suit CMS and/or ParNew needs; these work well on
  // sparc/solaris for certain applications, but would gain from
  // further optimization and tuning efforts, and would almost
--- 1124,1133 ----