truffle: src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp comparison

comparison src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp @ 526:818efdefcc99

6484956: G1: improve evacuation pause efficiency Summary: A bunch of performance optimizations to decrease GC pause times in G1. Reviewed-by: apetrusenko, jmasa, iveresov

author	tonyp
date	Fri, 16 Jan 2009 13:02:20 -0500
parents	65de26b5ea82
children	58054a18d735

comparison

equal deleted inserted replaced

-:65de26b5ea82
+:818efdefcc99
 // Summary information about popular objects; method to print it.
 NumberSeq _pop_obj_rc_at_copy;
 void print_popularity_summary_info() const;
+// This is used for a quick test on whether a reference points into
+// the collection set or not. Basically, we have an array, with one
+// byte per region, and that byte denotes whether the corresponding
+// region is in the collection set or not. The entry corresponding
+// the bottom of the heap, i.e., region 0, is pointed to by
+// _in_cset_fast_test_base.  The _in_cset_fast_test field has been
+// biased so that it actually points to address 0 of the address
+// space, to make the test as fast as possible (we can simply shift
+// the address to address into it, instead of having to subtract the
+// bottom of the heap from the address before shifting it; basically
+// it works in the same way the card table works).
+bool* _in_cset_fast_test;
+// The allocated array used for the fast test on whether a reference
+// points into the collection set or not. This field is also used to
+// free the array.
+bool* _in_cset_fast_test_base;
+// The length of the _in_cset_fast_test_base array.
+size_t _in_cset_fast_test_length;
 volatile unsigned _gc_time_stamp;
 size_t* _surviving_young_words;
 void setup_surviving_young_words();
 virtual void expand(size_t expand_bytes);
 // Do anything common to GC's.
 virtual void gc_prologue(bool full);
 virtual void gc_epilogue(bool full);
+// We register a region with the fast "in collection set" test. We
+// simply set to true the array slot corresponding to this region.
+void register_region_with_in_cset_fast_test(HeapRegion* r) {
+assert(_in_cset_fast_test_base != NULL, "sanity");
+assert(r->in_collection_set(), "invariant");
+int index = r->hrs_index();
+assert(0 <= (size_t) index && (size_t) index < _in_cset_fast_test_length,
+"invariant");
+assert(!_in_cset_fast_test_base[index], "invariant");
+_in_cset_fast_test_base[index] = true;
+}
+// This is a fast test on whether a reference points into the
+// collection set or not. It does not assume that the reference
+// points into the heap; if it doesn't, it will return false.
+bool in_cset_fast_test(oop obj) {
+assert(_in_cset_fast_test != NULL, "sanity");
+if (_g1_committed.contains((HeapWord*) obj)) {
+// no need to subtract the bottom of the heap from obj,
+// _in_cset_fast_test is biased
+size_t index = ((size_t) obj) >> HeapRegion::LogOfHRGrainBytes;
+bool ret = _in_cset_fast_test[index];
+// let's make sure the result is consistent with what the slower
+// test returns
+assert( ret || !obj_in_cs(obj), "sanity");
+assert(!ret ||  obj_in_cs(obj), "sanity");
+return ret;
+} else {
+return false;
+}
+}
 protected:
 // Shrink the garbage-first heap by at most the given size (in bytes!).
 // (Rounds down to a HeapRegion boundary.)

Mercurial > hg > truffle

comparison src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp @ 526:818efdefcc99