8354517: Parallel: JDK-8339668 causes up to 3.7x slowdown in openjdk.bench.vm.gc.systemgc

Reviewed-by: tschatzl, aboldtch, zgu

Author: albertnetymk

src/hotspot/share/gc/g1/g1ParScanThreadState.cpp

@@ -80,7 +80,7 @@ G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h,
     _surviving_young_words(nullptr),
     _surviving_words_length(collection_set->young_region_length() + 1),
     _old_gen_is_full(false),
-    _partial_array_splitter(g1h->partial_array_state_manager(), num_workers),
+    _partial_array_splitter(g1h->partial_array_state_manager(), num_workers, ParGCArrayScanChunk),
     _string_dedup_requests(),
     _max_num_optional_regions(collection_set->num_optional_regions()),
     _numa(g1h->numa()),

src/hotspot/share/gc/parallel/psCompactionManager.cpp

@@ -58,7 +58,7 @@ PreservedMarksSet* ParCompactionManager::_preserved_marks_set = nullptr;
 ParCompactionManager::ParCompactionManager(PreservedMarks* preserved_marks,
                                            ReferenceProcessor* ref_processor,
                                            uint parallel_gc_threads)
-  :_partial_array_splitter(_partial_array_state_manager, parallel_gc_threads),
+  :_partial_array_splitter(_partial_array_state_manager, parallel_gc_threads, ObjArrayMarkingStride),
    _mark_and_push_closure(this, ref_processor) {
 
   ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();

src/hotspot/share/gc/parallel/psPromotionManager.cpp

@@ -166,7 +166,7 @@ PartialArrayTaskStats* PSPromotionManager::partial_array_task_stats() {
 
 // Most members are initialized either by initialize() or reset().
 PSPromotionManager::PSPromotionManager()
-  : _partial_array_splitter(_partial_array_state_manager, ParallelGCThreads)
+  : _partial_array_splitter(_partial_array_state_manager, ParallelGCThreads, ParGCArrayScanChunk)
 {
   // We set the old lab's start array.
   _old_lab.set_start_array(old_gen()->start_array());

src/hotspot/share/gc/shared/partialArraySplitter.cpp

@@ -28,9 +28,10 @@
 #include "utilities/macros.hpp"
 
 PartialArraySplitter::PartialArraySplitter(PartialArrayStateManager* manager,
-                                           uint num_workers)
+                                           uint num_workers,
+                                           size_t chunk_size)
   : _allocator(manager),
-    _stepper(num_workers, ParGCArrayScanChunk)
+    _stepper(num_workers, chunk_size)
     TASKQUEUE_STATS_ONLY(COMMA _stats())
 {}
 

src/hotspot/share/gc/shared/partialArraySplitter.hpp

@@ -43,7 +43,9 @@ class PartialArraySplitter {
   TASKQUEUE_STATS_ONLY(PartialArrayTaskStats _stats;)
 
 public:
-  PartialArraySplitter(PartialArrayStateManager* manager, uint num_workers);
+  PartialArraySplitter(PartialArrayStateManager* manager,
+                       uint num_workers,
+                       size_t chunk_size);
   ~PartialArraySplitter() = default;
 
   NONCOPYABLE(PartialArraySplitter);