src/share/vm/gc_implementation/g1/concurrentMark.hpp

rev 2896 : 7121547: G1: High number mispredicted branches while iterating over the marking bitmap
Summary: There is a high number of mispredicted branches associated with calling BitMap::iteratate() from within CMBitMapRO::iterate(). Implement a version of CMBitMapRO::iterate() directly using inline-able routines.
Reviewed-by:

*** 82,93 ****
             "outside underlying space?");
      return _bm.at(heapWordToOffset(addr));
    }
  
    // iteration
!   bool iterate(BitMapClosure* cl) { return _bm.iterate(cl); }
!   bool iterate(BitMapClosure* cl, MemRegion mr);
  
    // Return the address corresponding to the next marked bit at or after
    // "addr", and before "limit", if "limit" is non-NULL.  If there is no
    // such bit, returns "limit" if that is non-NULL, or else "endWord()".
    HeapWord* getNextMarkedWordAddress(HeapWord* addr,
--- 82,93 ----
             "outside underlying space?");
      return _bm.at(heapWordToOffset(addr));
    }
  
    // iteration
!   inline bool iterate(BitMapClosure* cl, MemRegion mr);
!   inline bool iterate(BitMapClosure* cl);
  
    // Return the address corresponding to the next marked bit at or after
    // "addr", and before "limit", if "limit" is non-NULL.  If there is no
    // such bit, returns "limit" if that is non-NULL, or else "endWord()".
    HeapWord* getNextMarkedWordAddress(HeapWord* addr,