8027423: Parallel compact GC class unloading measurement includes symbol and string table time

Reviewed-by: mgerdin, jmasa

hotspot/src/share/vm/gc/g1/g1CollectedHeap.cpp

@@ -4098,14 +4098,10 @@ void G1CollectedHeap::parallel_cleaning(BoolObjectClosure* is_alive,
 
 void G1CollectedHeap::unlink_string_and_symbol_table(BoolObjectClosure* is_alive,
                                                      bool process_strings, bool process_symbols) {
-  {
+  { // Timing scope
     G1StringSymbolTableUnlinkTask g1_unlink_task(is_alive, process_strings, process_symbols);
     workers()->run_task(&g1_unlink_task);
   }
-
-  if (G1StringDedup::is_enabled()) {
-    G1StringDedup::unlink(is_alive);
-  }
 }
 
 class G1RedirtyLoggedCardsTask : public AbstractGangTask {

hotspot/src/share/vm/gc/g1/g1MarkSweep.cpp

@@ -154,17 +154,29 @@ void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading,
   // This is the point where the entire marking should have completed.
   assert(GenMarkSweep::_marking_stack.is_empty(), "Marking should have completed");
 
-  // Unload classes and purge the SystemDictionary.
+  {
-  bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive);
+    GCTraceTime(Debug, gc) trace("Class Unloading", gc_timer());
 
-  // Unload nmethods.
+    // Unload classes and purge the SystemDictionary.
-  CodeCache::do_unloading(&GenMarkSweep::is_alive, purged_class);
+    bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive);
 
-  // Prune dead klasses from subklass/sibling/implementor lists.
+    // Unload nmethods.
-  Klass::clean_weak_klass_links(&GenMarkSweep::is_alive);
+    CodeCache::do_unloading(&GenMarkSweep::is_alive, purged_class);
 
-  // Delete entries for dead interned string and clean up unreferenced symbols in symbol table.
+    // Prune dead klasses from subklass/sibling/implementor lists.
-  g1h->unlink_string_and_symbol_table(&GenMarkSweep::is_alive);
+    Klass::clean_weak_klass_links(&GenMarkSweep::is_alive);
+  }
+
+  {
+    GCTraceTime(Debug, gc) trace("Scrub String and Symbol Tables", gc_timer());
+    // Delete entries for dead interned string and clean up unreferenced symbols in symbol table.
+    g1h->unlink_string_and_symbol_table(&GenMarkSweep::is_alive);
+  }
+
+  if (G1StringDedup::is_enabled()) {
+    GCTraceTime(Debug, gc) trace("String Deduplication Unlink", gc_timer());
+    G1StringDedup::unlink(&GenMarkSweep::is_alive);
+  }
 
   if (VerifyDuringGC) {
     HandleMark hm;  // handle scope

hotspot/src/share/vm/gc/parallel/psMarkSweep.cpp

@@ -533,20 +533,31 @@ void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
   // This is the point where the entire marking should have completed.
   assert(_marking_stack.is_empty(), "Marking should have completed");
 
-  // Unload classes and purge the SystemDictionary.
+  {
-  bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
+    GCTraceTime(Debug, gc) t("Class Unloading", _gc_timer);
 
-  // Unload nmethods.
+    // Unload classes and purge the SystemDictionary.
-  CodeCache::do_unloading(is_alive_closure(), purged_class);
+    bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
 
-  // Prune dead klasses from subklass/sibling/implementor lists.
+    // Unload nmethods.
-  Klass::clean_weak_klass_links(is_alive_closure());
+    CodeCache::do_unloading(is_alive_closure(), purged_class);
 
-  // Delete entries for dead interned strings.
+    // Prune dead klasses from subklass/sibling/implementor lists.
-  StringTable::unlink(is_alive_closure());
+    Klass::clean_weak_klass_links(is_alive_closure());
+  }
+
+  {
+    GCTraceTime(Debug, gc) t("Scrub String Table", _gc_timer);
+    // Delete entries for dead interned strings.
+    StringTable::unlink(is_alive_closure());
+  }
+
+  {
+    GCTraceTime(Debug, gc) t("Scrub Symbol Table", _gc_timer);
+    // Clean up unreferenced symbols in symbol table.
+    SymbolTable::unlink();
+  }
 
-  // Clean up unreferenced symbols in symbol table.
-  SymbolTable::unlink();
   _gc_tracer->report_object_count_after_gc(is_alive_closure());
 }
 

hotspot/src/share/vm/gc/parallel/psParallelCompact.cpp

@@ -2103,25 +2103,34 @@ void PSParallelCompact::marking_phase(ParCompactionManager* cm,
     gc_tracer->report_gc_reference_stats(stats);
   }
 
-  GCTraceTime(Trace, gc) tm_m("Class Unloading", &_gc_timer);
-
   // This is the point where the entire marking should have completed.
   assert(cm->marking_stacks_empty(), "Marking should have completed");
 
-  // Follow system dictionary roots and unload classes.
+  {
-  bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
+    GCTraceTime(Debug, gc) tm_m("Class Unloading", &_gc_timer);
 
-  // Unload nmethods.
+    // Follow system dictionary roots and unload classes.
-  CodeCache::do_unloading(is_alive_closure(), purged_class);
+    bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
 
-  // Prune dead klasses from subklass/sibling/implementor lists.
+    // Unload nmethods.
-  Klass::clean_weak_klass_links(is_alive_closure());
+    CodeCache::do_unloading(is_alive_closure(), purged_class);
 
-  // Delete entries for dead interned strings.
+    // Prune dead klasses from subklass/sibling/implementor lists.
-  StringTable::unlink(is_alive_closure());
+    Klass::clean_weak_klass_links(is_alive_closure());
+  }
+
+  {
+    GCTraceTime(Debug, gc) t("Scrub String Table", &_gc_timer);
+    // Delete entries for dead interned strings.
+    StringTable::unlink(is_alive_closure());
+  }
+
+  {
+    GCTraceTime(Debug, gc) t("Scrub Symbol Table", &_gc_timer);
+    // Clean up unreferenced symbols in symbol table.
+    SymbolTable::unlink();
+  }
 
-  // Clean up unreferenced symbols in symbol table.
-  SymbolTable::unlink();
   _gc_tracer.report_object_count_after_gc(is_alive_closure());
 }
 

hotspot/src/share/vm/gc/serial/genMarkSweep.cpp

@@ -218,20 +218,30 @@ void GenMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
   // This is the point where the entire marking should have completed.
   assert(_marking_stack.is_empty(), "Marking should have completed");
 
-  // Unload classes and purge the SystemDictionary.
+  {
-  bool purged_class = SystemDictionary::do_unloading(&is_alive);
+    GCTraceTime(Debug, gc) tm_m("Class Unloading", gc_timer());
 
-  // Unload nmethods.
+    // Unload classes and purge the SystemDictionary.
-  CodeCache::do_unloading(&is_alive, purged_class);
+    bool purged_class = SystemDictionary::do_unloading(&is_alive);
 
-  // Prune dead klasses from subklass/sibling/implementor lists.
+    // Unload nmethods.
-  Klass::clean_weak_klass_links(&is_alive);
+    CodeCache::do_unloading(&is_alive, purged_class);
 
-  // Delete entries for dead interned strings.
+    // Prune dead klasses from subklass/sibling/implementor lists.
-  StringTable::unlink(&is_alive);
+    Klass::clean_weak_klass_links(&is_alive);
+  }
 
-  // Clean up unreferenced symbols in symbol table.
+  {
-  SymbolTable::unlink();
+    GCTraceTime(Debug, gc) t("Scrub String Table", gc_timer());
+    // Delete entries for dead interned strings.
+    StringTable::unlink(&is_alive);
+  }
+
+  {
+    GCTraceTime(Debug, gc) t("Scrub Symbol Table", gc_timer());
+    // Clean up unreferenced symbols in symbol table.
+    SymbolTable::unlink();
+  }
 
   gc_tracer()->report_object_count_after_gc(&is_alive);
 }