--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentG1Refine.cpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentG1Refine.cpp	Fri Oct 02 16:12:07 2009 -0400
@@ -377,3 +377,11 @@
   _g1h->g1_policy()->record_cc_clear_time(elapsed * 1000.0);
 #endif
 }
+
+void ConcurrentG1Refine::print_worker_threads_on(outputStream* st) const {
+  for (int i = 0; i < _n_threads; ++i) {
+    _threads[i]->print_on(st);
+    st->cr();
+  }
+}
+

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentG1Refine.hpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentG1Refine.hpp	Fri Oct 02 16:12:07 2009 -0400
@@ -179,4 +179,6 @@
   void clear_and_record_card_counts();
 
   static size_t thread_num();
+
+  void print_worker_threads_on(outputStream* st) const;
 };

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentG1RefineThread.cpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentG1RefineThread.cpp	Fri Oct 02 16:12:07 2009 -0400
@@ -204,8 +204,12 @@
   if (G1TraceConcurrentRefinement) gclog_or_tty->print_cr("G1-Refine-stop");
 }
 
-void ConcurrentG1RefineThread::print() {
-  gclog_or_tty->print("\"Concurrent G1 Refinement Thread\" ");
-  Thread::print();
-  gclog_or_tty->cr();
+void ConcurrentG1RefineThread::print() const {
+  print_on(tty);
 }
+
+void ConcurrentG1RefineThread::print_on(outputStream* st) const {
+  st->print("\"G1 Concurrent Refinement Thread#%d\" ", _worker_id);
+  Thread::print_on(st);
+  st->cr();
+}

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentG1RefineThread.hpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentG1RefineThread.hpp	Fri Oct 02 16:12:07 2009 -0400
@@ -77,7 +77,8 @@
                            int worker_id_offset, int worker_id);
 
   // Printing
-  void print();
+  void print() const;
+  void print_on(outputStream* st) const;
 
   // Total virtual time so far.
   double vtime_accum() { return _vtime_accum; }

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp	Fri Oct 02 16:12:07 2009 -0400
@@ -543,7 +543,7 @@
 #endif
 
     guarantee( parallel_marking_threads() > 0, "peace of mind" );
-    _parallel_workers = new WorkGang("Parallel Marking Threads",
+    _parallel_workers = new WorkGang("G1 Parallel Marking Threads",
                                      (int) parallel_marking_threads(), false, true);
     if (_parallel_workers == NULL)
       vm_exit_during_initialization("Failed necessary allocation.");
@@ -2637,6 +2637,10 @@
                 cmThread()->vtime_count_accum());
 }
 
+void ConcurrentMark::print_worker_threads_on(outputStream* st) const {
+  _parallel_workers->print_worker_threads_on(st);
+}
+
 // Closures
 // XXX: there seems to be a lot of code  duplication here;
 // should refactor and consolidate the shared code.

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.hpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.hpp	Fri Oct 02 16:12:07 2009 -0400
@@ -723,6 +723,8 @@
 
   void print_summary_info();
 
+  void print_worker_threads_on(outputStream* st) const;
+
   // The following indicate whether a given verbose level has been
   // set. Notice that anything above stats is conditional to
   // _MARKING_VERBOSE_ having been set to 1

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentMarkThread.cpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentMarkThread.cpp	Fri Oct 02 16:12:07 2009 -0400
@@ -286,10 +286,14 @@
   }
 }
 
-void ConcurrentMarkThread::print() {
-  gclog_or_tty->print("\"Concurrent Mark GC Thread\" ");
-  Thread::print();
-  gclog_or_tty->cr();
+void ConcurrentMarkThread::print() const {
+  print_on(tty);
+}
+
+void ConcurrentMarkThread::print_on(outputStream* st) const {
+  st->print("\"G1 Main Concurrent Mark GC Thread\" ");
+  Thread::print_on(st);
+  st->cr();
 }
 
 void ConcurrentMarkThread::sleepBeforeNextCycle() {

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentMarkThread.hpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentMarkThread.hpp	Fri Oct 02 16:12:07 2009 -0400
@@ -57,7 +57,8 @@
   static SurrogateLockerThread* slt() { return _slt; }
 
   // Printing
-  void print();
+  void print_on(outputStream* st) const;
+  void print() const;
 
   // Total virtual time so far.
   double vtime_accum();

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentZFThread.cpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentZFThread.cpp	Fri Oct 02 16:12:07 2009 -0400
@@ -157,10 +157,14 @@
   }
 }
 
-void ConcurrentZFThread::print() {
-  gclog_or_tty->print("\"Concurrent ZF Thread\" ");
-  Thread::print();
-  gclog_or_tty->cr();
+void ConcurrentZFThread::print() const {
+  print_on(tty);
+}
+
+void ConcurrentZFThread::print_on(outputStream* st) const {
+  st->print("\"G1 Concurrent Zero-Fill Thread\" ");
+  Thread::print_on(st);
+  st->cr();
 }
 
 

--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentZFThread.hpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentZFThread.hpp	Fri Oct 02 16:12:07 2009 -0400
@@ -61,7 +61,8 @@
   virtual void run();
 
   // Printing
-  void print();
+  void print_on(outputStream* st) const;
+  void print() const;
 
   // Waits until "r" has been zero-filled.  Requires caller to hold the
   // ZF_mon.

--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Mon Oct 05 05:51:22 2009 -0700
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Fri Oct 02 16:12:07 2009 -0400
@@ -2383,27 +2383,18 @@
   _hrs->iterate(&blk);
 }
 
-class PrintOnThreadsClosure : public ThreadClosure {
-  outputStream* _st;
-public:
-  PrintOnThreadsClosure(outputStream* st) : _st(st) { }
-  virtual void do_thread(Thread *t) {
-    t->print_on(_st);
-  }
-};
-
 void G1CollectedHeap::print_gc_threads_on(outputStream* st) const {
   if (ParallelGCThreads > 0) {
-    workers()->print_worker_threads();
-  }
-  st->print("\"G1 concurrent mark GC Thread\" ");
-  _cmThread->print();
+    workers()->print_worker_threads_on(st);
+  }
+
+  _cmThread->print_on(st);
   st->cr();
-  st->print("\"G1 concurrent refinement GC Threads\" ");
-  PrintOnThreadsClosure p(st);
-  _cg1r->threads_do(&p);
-  st->cr();
-  st->print("\"G1 zero-fill GC Thread\" ");
+
+  _cm->print_worker_threads_on(st);
+
+  _cg1r->print_worker_threads_on(st);
+
   _czft->print_on(st);
   st->cr();
 }