Merge

src/share/vm/gc_implementation/g1/concurrentG1RefineThread.cpp

@@ -39,7 +39,6 @@ ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r, ConcurrentG1RefineThread *nex
   _next(next),
   _cg1r(cg1r),
   _vtime_accum(0.0),
-  _co_tracker(G1CRGroup),
   _interval_ms(5.0)
 {
   create_and_start();
@@ -76,9 +75,6 @@ void ConcurrentG1RefineThread::run() {
   _vtime_start = os::elapsedVTime();
   wait_for_universe_init();
 
-  _co_tracker.enable();
-  _co_tracker.start();
-
   while (!_should_terminate) {
     DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
     // Wait for completed log buffers to exist.
@@ -147,7 +143,6 @@ void ConcurrentG1RefineThread::run() {
         }
         break;
       }
-      _co_tracker.update(false);
 
       // Check if we need to activate the next thread.
       if (curr_buffer_num > next_threshold && _next != NULL && !_next->is_active()) {
@@ -168,7 +163,6 @@ void ConcurrentG1RefineThread::run() {
       }
       n_logs++;
     }
-    _co_tracker.update(false);
     _sts.leave();
 
     if (os::supports_vtime()) {
@@ -177,9 +171,6 @@ void ConcurrentG1RefineThread::run() {
       _vtime_accum = 0.0;
     }
   }
-  _sts.join();
-  _co_tracker.update(true);
-  _sts.leave();
   assert(_should_terminate, "just checking");
 
   terminate();

src/share/vm/gc_implementation/g1/concurrentG1RefineThread.hpp

@@ -51,7 +51,6 @@ class ConcurrentG1RefineThread: public ConcurrentGCThread {
  private:
   ConcurrentG1Refine*              _cg1r;
 
-  COTracker                        _co_tracker;
   double                           _interval_ms;
 
   void decreaseInterval(int processing_time_ms) {

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

@@ -433,8 +433,7 @@ ConcurrentMark::ConcurrentMark(ReservedSpace rs,
   _total_counting_time(0.0),
   _total_rs_scrub_time(0.0),
 
-  _parallel_workers(NULL),
-  _cleanup_co_tracker(G1CLGroup)
+  _parallel_workers(NULL)
 {
   CMVerboseLevel verbose_level =
     (CMVerboseLevel) G1MarkingVerboseLevel;
@@ -823,18 +822,6 @@ void ConcurrentMark::checkpointRootsInitialPost() {
   // when marking is on. So, it's also called at the end of the
   // initial-mark pause to update the heap end, if the heap expands
   // during it. No need to call it here.
-
-  guarantee( !_cleanup_co_tracker.enabled(), "invariant" );
-
-  size_t max_marking_threads =
-    MAX2((size_t) 1, parallel_marking_threads());
-  for (int i = 0; i < (int)_max_task_num; ++i) {
-    _tasks[i]->enable_co_tracker();
-    if (i < (int) max_marking_threads)
-      _tasks[i]->reset_co_tracker(marking_task_overhead());
-    else
-      _tasks[i]->reset_co_tracker(0.0);
-  }
 }
 
 // Checkpoint the roots into this generation from outside
@@ -845,7 +832,6 @@ void ConcurrentMark::checkpointRootsInitial() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 
   double start = os::elapsedTime();
-  GCOverheadReporter::recordSTWStart(start);
 
   G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy();
   g1p->record_concurrent_mark_init_start();
@@ -876,7 +862,6 @@ void ConcurrentMark::checkpointRootsInitial() {
   // Statistics.
   double end = os::elapsedTime();
   _init_times.add((end - start) * 1000.0);
-  GCOverheadReporter::recordSTWEnd(end);
 
   g1p->record_concurrent_mark_init_end();
 }
@@ -1035,7 +1020,6 @@ public:
 
     guarantee( (size_t)worker_i < _cm->active_tasks(), "invariant" );
     CMTask* the_task = _cm->task(worker_i);
-    the_task->start_co_tracker();
     the_task->record_start_time();
     if (!_cm->has_aborted()) {
       do {
@@ -1061,8 +1045,6 @@ public:
         double end_time2_sec = os::elapsedTime();
         double elapsed_time2_sec = end_time2_sec - start_time_sec;
 
-        the_task->update_co_tracker();
-
 #if 0
           gclog_or_tty->print_cr("CM: elapsed %1.4lf ms, sleep %1.4lf ms, "
                                  "overhead %1.4lf",
@@ -1079,7 +1061,6 @@ public:
     ConcurrentGCThread::stsLeave();
 
     double end_vtime = os::elapsedVTime();
-    the_task->update_co_tracker(true);
     _cm->update_accum_task_vtime(worker_i, end_vtime - start_vtime);
   }
 
@@ -1133,7 +1114,6 @@ void ConcurrentMark::checkpointRootsFinal(bool clear_all_soft_refs) {
   g1p->record_concurrent_mark_remark_start();
 
   double start = os::elapsedTime();
-  GCOverheadReporter::recordSTWStart(start);
 
   checkpointRootsFinalWork();
 
@@ -1173,11 +1153,6 @@ void ConcurrentMark::checkpointRootsFinal(bool clear_all_soft_refs) {
   _remark_weak_ref_times.add((now - mark_work_end) * 1000.0);
   _remark_times.add((now - start) * 1000.0);
 
-  GCOverheadReporter::recordSTWEnd(now);
-  for (int i = 0; i < (int)_max_task_num; ++i)
-    _tasks[i]->disable_co_tracker();
-  _cleanup_co_tracker.enable();
-  _cleanup_co_tracker.reset(cleanup_task_overhead());
   g1p->record_concurrent_mark_remark_end();
 }
 
@@ -1188,7 +1163,6 @@ class CalcLiveObjectsClosure: public HeapRegionClosure {
 
   CMBitMapRO* _bm;
   ConcurrentMark* _cm;
-  COTracker* _co_tracker;
   bool _changed;
   bool _yield;
   size_t _words_done;
@@ -1216,12 +1190,10 @@ class CalcLiveObjectsClosure: public HeapRegionClosure {
 public:
   CalcLiveObjectsClosure(bool final,
                          CMBitMapRO *bm, ConcurrentMark *cm,
-                         BitMap* region_bm, BitMap* card_bm,
-                         COTracker* co_tracker) :
+                         BitMap* region_bm, BitMap* card_bm) :
     _bm(bm), _cm(cm), _changed(false), _yield(true),
     _words_done(0), _tot_live(0), _tot_used(0),
-    _region_bm(region_bm), _card_bm(card_bm),
-    _final(final), _co_tracker(co_tracker),
+    _region_bm(region_bm), _card_bm(card_bm),_final(final),
     _regions_done(0), _start_vtime_sec(0.0)
   {
     _bottom_card_num =
@@ -1265,9 +1237,6 @@ public:
   }
 
   bool doHeapRegion(HeapRegion* hr) {
-    if (_co_tracker != NULL)
-      _co_tracker->update();
-
     if (!_final && _regions_done == 0)
       _start_vtime_sec = os::elapsedVTime();
 
@@ -1396,12 +1365,6 @@ public:
         if (elapsed_vtime_sec > (10.0 / 1000.0)) {
           jlong sleep_time_ms =
             (jlong) (elapsed_vtime_sec * _cm->cleanup_sleep_factor() * 1000.0);
-#if 0
-          gclog_or_tty->print_cr("CL: elapsed %1.4lf ms, sleep %1.4lf ms, "
-                                 "overhead %1.4lf",
-                                 elapsed_vtime_sec * 1000.0, (double) sleep_time_ms,
-                                 _co_tracker->concOverhead(os::elapsedTime()));
-#endif
           os::sleep(Thread::current(), sleep_time_ms, false);
           _start_vtime_sec = end_vtime_sec;
         }
@@ -1421,15 +1384,11 @@ public:
 
 
 void ConcurrentMark::calcDesiredRegions() {
-  guarantee( _cleanup_co_tracker.enabled(), "invariant" );
-  _cleanup_co_tracker.start();
-
   _region_bm.clear();
   _card_bm.clear();
   CalcLiveObjectsClosure calccl(false /*final*/,
                                 nextMarkBitMap(), this,
-                                &_region_bm, &_card_bm,
-                                &_cleanup_co_tracker);
+                                &_region_bm, &_card_bm);
   G1CollectedHeap *g1h = G1CollectedHeap::heap();
   g1h->heap_region_iterate(&calccl);
 
@@ -1437,8 +1396,6 @@ void ConcurrentMark::calcDesiredRegions() {
     calccl.reset();
     g1h->heap_region_iterate(&calccl);
   } while (calccl.changed());
-
-  _cleanup_co_tracker.update(true);
 }
 
 class G1ParFinalCountTask: public AbstractGangTask {
@@ -1472,8 +1429,7 @@ public:
   void work(int i) {
     CalcLiveObjectsClosure calccl(true /*final*/,
                                   _bm, _g1h->concurrent_mark(),
-                                  _region_bm, _card_bm,
-                                  NULL /* CO tracker */);
+                                  _region_bm, _card_bm);
     calccl.no_yield();
     if (ParallelGCThreads > 0) {
       _g1h->heap_region_par_iterate_chunked(&calccl, i,
@@ -1663,13 +1619,10 @@ void ConcurrentMark::cleanup() {
                      /* prev marking */ true);
   }
 
-  _cleanup_co_tracker.disable();
-
   G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy();
   g1p->record_concurrent_mark_cleanup_start();
 
   double start = os::elapsedTime();
-  GCOverheadReporter::recordSTWStart(start);
 
   // Do counting once more with the world stopped for good measure.
   G1ParFinalCountTask g1_par_count_task(g1h, nextMarkBitMap(),
@@ -1774,7 +1727,6 @@ void ConcurrentMark::cleanup() {
   // Statistics.
   double end = os::elapsedTime();
   _cleanup_times.add((end - start) * 1000.0);
-  GCOverheadReporter::recordSTWEnd(end);
 
   // G1CollectedHeap::heap()->print();
   // gclog_or_tty->print_cr("HEAP GC TIME STAMP : %d",
@@ -2625,24 +2577,6 @@ void ConcurrentMark::registerCSetRegion(HeapRegion* hr) {
     _should_gray_objects = true;
 }
 
-void ConcurrentMark::disable_co_trackers() {
-  if (has_aborted()) {
-    if (_cleanup_co_tracker.enabled())
-      _cleanup_co_tracker.disable();
-    for (int i = 0; i < (int)_max_task_num; ++i) {
-      CMTask* task = _tasks[i];
-      if (task->co_tracker_enabled())
-        task->disable_co_tracker();
-    }
-  } else {
-    guarantee( !_cleanup_co_tracker.enabled(), "invariant" );
-    for (int i = 0; i < (int)_max_task_num; ++i) {
-      CMTask* task = _tasks[i];
-      guarantee( !task->co_tracker_enabled(), "invariant" );
-    }
-  }
-}
-
 // abandon current marking iteration due to a Full GC
 void ConcurrentMark::abort() {
   // Clear all marks to force marking thread to do nothing
@@ -4018,7 +3952,6 @@ CMTask::CMTask(int task_id,
                CMTaskQueue* task_queue,
                CMTaskQueueSet* task_queues)
   : _g1h(G1CollectedHeap::heap()),
-    _co_tracker(G1CMGroup),
     _task_id(task_id), _cm(cm),
     _claimed(false),
     _nextMarkBitMap(NULL), _hash_seed(17),

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

@@ -407,8 +407,6 @@ protected:
   // verbose level
   CMVerboseLevel          _verbose_level;
 
-  COTracker               _cleanup_co_tracker;
-
   // These two fields are used to implement the optimisation that
   // avoids pushing objects on the global/region stack if there are
   // no collection set regions above the lowest finger.
@@ -720,8 +718,6 @@ public:
   // Called to abort the marking cycle after a Full GC takes palce.
   void abort();
 
-  void disable_co_trackers();
-
   // This prints the global/local fingers. It is used for debugging.
   NOT_PRODUCT(void print_finger();)
 
@@ -773,9 +769,6 @@ private:
   // number of calls to this task
   int                         _calls;
 
-  // concurrent overhead over a single CPU for this task
-  COTracker                   _co_tracker;
-
   // when the virtual timer reaches this time, the marking step should
   // exit
   double                      _time_target_ms;
@@ -928,27 +921,6 @@ public:
 
   void set_concurrent(bool concurrent) { _concurrent = concurrent; }
 
-  void enable_co_tracker() {
-    guarantee( !_co_tracker.enabled(), "invariant" );
-    _co_tracker.enable();
-  }
-  void disable_co_tracker() {
-    guarantee( _co_tracker.enabled(), "invariant" );
-    _co_tracker.disable();
-  }
-  bool co_tracker_enabled() {
-    return _co_tracker.enabled();
-  }
-  void reset_co_tracker(double starting_conc_overhead = 0.0) {
-    _co_tracker.reset(starting_conc_overhead);
-  }
-  void start_co_tracker() {
-    _co_tracker.start();
-  }
-  void update_co_tracker(bool force_end = false) {
-    _co_tracker.update(force_end);
-  }
-
   // The main method of this class which performs a marking step
   // trying not to exceed the given duration. However, it might exit
   // prematurely, according to some conditions (i.e. SATB buffers are

src/share/vm/gc_implementation/g1/concurrentMarkThread.cpp

@@ -260,10 +260,6 @@ void ConcurrentMarkThread::run() {
         }
       }
 
-      _sts.join();
-      _cm->disable_co_trackers();
-      _sts.leave();
-
       // we now want to allow clearing of the marking bitmap to be
       // suspended by a collection pause.
       _sts.join();

src/share/vm/gc_implementation/g1/concurrentZFThread.cpp

@@ -35,8 +35,7 @@ int ConcurrentZFThread::_zf_waits = 0;
 int ConcurrentZFThread::_regions_filled = 0;
 
 ConcurrentZFThread::ConcurrentZFThread() :
-  ConcurrentGCThread(),
-  _co_tracker(G1ZFGroup)
+  ConcurrentGCThread()
 {
   create_and_start();
 }
@@ -71,8 +70,6 @@ void ConcurrentZFThread::run() {
   Thread* thr_self = Thread::current();
   _vtime_start = os::elapsedVTime();
   wait_for_universe_init();
-  _co_tracker.enable();
-  _co_tracker.start();
 
   G1CollectedHeap* g1 = G1CollectedHeap::heap();
   _sts.join();
@@ -135,10 +132,7 @@ void ConcurrentZFThread::run() {
     }
     _vtime_accum = (os::elapsedVTime() - _vtime_start);
     _sts.join();
-
-    _co_tracker.update();
   }
-  _co_tracker.update(false);
   _sts.leave();
 
   assert(_should_terminate, "just checking");

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

@@ -42,8 +42,6 @@ class ConcurrentZFThread: public ConcurrentGCThread {
   // Number of regions CFZ thread fills.
   static int _regions_filled;
 
-  COTracker _co_tracker;
-
   double _vtime_start;  // Initial virtual time.
 
   // These are static because the "print_summary_info" method is, and

src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp

@@ -927,7 +927,6 @@ void G1CollectedHeap::do_collection(bool full, bool clear_all_soft_refs,
     TraceTime t(full ? "Full GC (System.gc())" : "Full GC", PrintGC, true, gclog_or_tty);
 
     double start = os::elapsedTime();
-    GCOverheadReporter::recordSTWStart(start);
     g1_policy()->record_full_collection_start();
 
     gc_prologue(true);
@@ -1049,7 +1048,6 @@ void G1CollectedHeap::do_collection(bool full, bool clear_all_soft_refs,
     }
 
     double end = os::elapsedTime();
-    GCOverheadReporter::recordSTWEnd(end);
     g1_policy()->record_full_collection_end();
 
 #ifdef TRACESPINNING
@@ -1610,9 +1608,6 @@ jint G1CollectedHeap::initialize() {
   // Do later initialization work for concurrent refinement.
   _cg1r->init();
 
-  const char* group_names[] = { "CR", "ZF", "CM", "CL" };
-  GCOverheadReporter::initGCOverheadReporter(4, group_names);
-
   return JNI_OK;
 }
 
@@ -2431,8 +2426,6 @@ void G1CollectedHeap::print_tracing_info() const {
   }
   g1_policy()->print_yg_surv_rate_info();
 
-  GCOverheadReporter::printGCOverhead();
-
   SpecializationStats::print();
 }
 
@@ -2669,7 +2662,6 @@ G1CollectedHeap::do_collection_pause_at_safepoint() {
       // The elapsed time induced by the start time below deliberately elides
       // the possible verification above.
       double start_time_sec = os::elapsedTime();
-      GCOverheadReporter::recordSTWStart(start_time_sec);
       size_t start_used_bytes = used();
 
       g1_policy()->record_collection_pause_start(start_time_sec,
@@ -2798,7 +2790,6 @@ G1CollectedHeap::do_collection_pause_at_safepoint() {
       double end_time_sec = os::elapsedTime();
       double pause_time_ms = (end_time_sec - start_time_sec) * MILLIUNITS;
       g1_policy()->record_pause_time_ms(pause_time_ms);
-      GCOverheadReporter::recordSTWEnd(end_time_sec);
       g1_policy()->record_collection_pause_end(abandoned);
 
       assert(regions_accounted_for(), "Region leakage.");

src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp

@@ -993,8 +993,6 @@ void G1CollectorPolicy::record_full_collection_end() {
   double full_gc_time_sec = end_sec - _cur_collection_start_sec;
   double full_gc_time_ms = full_gc_time_sec * 1000.0;
 
-  checkpoint_conc_overhead();
-
   _all_full_gc_times_ms->add(full_gc_time_ms);
 
   update_recent_gc_times(end_sec, full_gc_time_ms);
@@ -1164,7 +1162,6 @@ void G1CollectorPolicy::record_concurrent_mark_init_end() {
   double end_time_sec = os::elapsedTime();
   double elapsed_time_ms = (end_time_sec - _mark_init_start_sec) * 1000.0;
   _concurrent_mark_init_times_ms->add(elapsed_time_ms);
-  checkpoint_conc_overhead();
   record_concurrent_mark_init_end_pre(elapsed_time_ms);
 
   _mmu_tracker->add_pause(_mark_init_start_sec, end_time_sec, true);
@@ -1178,7 +1175,6 @@ void G1CollectorPolicy::record_concurrent_mark_remark_start() {
 void G1CollectorPolicy::record_concurrent_mark_remark_end() {
   double end_time_sec = os::elapsedTime();
   double elapsed_time_ms = (end_time_sec - _mark_remark_start_sec)*1000.0;
-  checkpoint_conc_overhead();
   _concurrent_mark_remark_times_ms->add(elapsed_time_ms);
   _cur_mark_stop_world_time_ms += elapsed_time_ms;
   _prev_collection_pause_end_ms += elapsed_time_ms;
@@ -1210,7 +1206,6 @@ record_concurrent_mark_cleanup_end_work1(size_t freed_bytes,
 
 // The important thing about this is that it includes "os::elapsedTime".
 void G1CollectorPolicy::record_concurrent_mark_cleanup_end_work2() {
-  checkpoint_conc_overhead();
   double end_time_sec = os::elapsedTime();
   double elapsed_time_ms = (end_time_sec - _mark_cleanup_start_sec)*1000.0;
   _concurrent_mark_cleanup_times_ms->add(elapsed_time_ms);
@@ -1425,8 +1420,6 @@ void G1CollectorPolicy::record_collection_pause_end(bool abandoned) {
   }
 #endif // PRODUCT
 
-  checkpoint_conc_overhead();
-
   if (in_young_gc_mode()) {
     last_pause_included_initial_mark = _should_initiate_conc_mark;
     if (last_pause_included_initial_mark)
@@ -2525,19 +2518,6 @@ region_num_to_mbs(int length) {
 }
 #endif // PRODUCT
 
-void
-G1CollectorPolicy::checkpoint_conc_overhead() {
-  double conc_overhead = 0.0;
-  if (G1AccountConcurrentOverhead)
-    conc_overhead = COTracker::totalPredConcOverhead();
-  _mmu_tracker->update_conc_overhead(conc_overhead);
-#if 0
-  gclog_or_tty->print(" CO %1.4lf TARGET %1.4lf",
-             conc_overhead, _mmu_tracker->max_gc_time());
-#endif
-}
-
-
 size_t G1CollectorPolicy::max_regions(int purpose) {
   switch (purpose) {
     case GCAllocForSurvived:

src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp

@@ -981,8 +981,6 @@ public:
   void set_should_initiate_conc_mark()  { _should_initiate_conc_mark = true; }
   void unset_should_initiate_conc_mark(){ _should_initiate_conc_mark = false; }
 
-  void checkpoint_conc_overhead();
-
   // If an expansion would be appropriate, because recent GC overhead had
   // exceeded the desired limit, return an amount to expand by.
   virtual size_t expansion_amount();

src/share/vm/gc_implementation/g1/g1MMUTracker.cpp

@@ -37,21 +37,7 @@
 
 G1MMUTracker::G1MMUTracker(double time_slice, double max_gc_time) :
   _time_slice(time_slice),
-  _max_gc_time(max_gc_time),
-  _conc_overhead_time_sec(0.0) { }
-
-void
-G1MMUTracker::update_conc_overhead(double conc_overhead) {
-  double conc_overhead_time_sec = _time_slice * conc_overhead;
-  if (conc_overhead_time_sec > 0.9 * _max_gc_time) {
-    // We are screwed, as we only seem to have <10% of the soft
-    // real-time goal available for pauses. Let's admit defeat and
-    // allow something more generous as a pause target.
-    conc_overhead_time_sec = 0.75 * _max_gc_time;
-  }
-
-  _conc_overhead_time_sec = conc_overhead_time_sec;
-}
+  _max_gc_time(max_gc_time) { }
 
 G1MMUTrackerQueue::G1MMUTrackerQueue(double time_slice, double max_gc_time) :
   G1MMUTracker(time_slice, max_gc_time),
@@ -128,7 +114,7 @@ double G1MMUTrackerQueue::longest_pause_internal(double current_time) {
 
   while( 1 ) {
     double gc_time =
-      calculate_gc_time(current_time + target_time) + _conc_overhead_time_sec;
+      calculate_gc_time(current_time + target_time);
     double diff = target_time + gc_time - _max_gc_time;
     if (!is_double_leq_0(diff)) {
       target_time -= diff;

src/share/vm/gc_implementation/g1/g1MMUTracker.hpp

@@ -33,19 +33,15 @@ protected:
   double          _time_slice;
   double          _max_gc_time; // this is per time slice
 
-  double          _conc_overhead_time_sec;
-
 public:
   G1MMUTracker(double time_slice, double max_gc_time);
 
-  void update_conc_overhead(double conc_overhead);
-
   virtual void add_pause(double start, double end, bool gc_thread) = 0;
   virtual double longest_pause(double current_time) = 0;
   virtual double when_sec(double current_time, double pause_time) = 0;
 
   double max_gc_time() {
-    return _max_gc_time - _conc_overhead_time_sec;
+    return _max_gc_time;
   }
 
   inline bool now_max_gc(double current_time) {

src/share/vm/gc_implementation/g1/g1_globals.hpp

@@ -37,10 +37,6 @@
   develop(intx, G1MarkingOverheadPercent, 0,                                \
           "Overhead of concurrent marking")                                 \
                                                                             \
-  develop(bool, G1AccountConcurrentOverhead, false,                         \
-          "Whether soft real-time compliance in G1 will take into account"  \
-          "concurrent overhead")                                            \
-                                                                            \
   product(intx, G1YoungGenSize, 0,                                          \
           "Size of the G1 young generation, 0 is the adaptive policy")      \
                                                                             \

src/share/vm/gc_implementation/includeDB_gc_g1

@@ -64,14 +64,12 @@ concurrentG1RefineThread.cpp		mutexLocker.hpp
 concurrentG1RefineThread.cpp		resourceArea.hpp
 
 concurrentG1RefineThread.hpp		concurrentGCThread.hpp
-concurrentG1RefineThread.hpp		coTracker.hpp
 
 concurrentMark.cpp			concurrentMark.hpp
 concurrentMark.cpp			concurrentMarkThread.inline.hpp
 concurrentMark.cpp			g1CollectedHeap.inline.hpp
 concurrentMark.cpp                      g1CollectorPolicy.hpp
 concurrentMark.cpp                      g1RemSet.hpp
-concurrentMark.cpp		        gcOverheadReporter.hpp
 concurrentMark.cpp		        genOopClosures.inline.hpp
 concurrentMark.cpp                      heapRegionRemSet.hpp
 concurrentMark.cpp                      heapRegionSeq.inline.hpp
@@ -82,7 +80,6 @@ concurrentMark.cpp                      referencePolicy.hpp
 concurrentMark.cpp			resourceArea.hpp
 concurrentMark.cpp			symbolTable.hpp
 
-concurrentMark.hpp			coTracker.hpp
 concurrentMark.hpp			heapRegion.hpp
 concurrentMark.hpp			taskqueue.hpp
 
@@ -107,7 +104,6 @@ concurrentZFThread.cpp			mutexLocker.hpp
 concurrentZFThread.cpp			space.inline.hpp
 
 concurrentZFThread.hpp			concurrentGCThread.hpp
-concurrentZFThread.hpp			coTracker.hpp
 
 dirtyCardQueue.cpp                      atomic.hpp
 dirtyCardQueue.cpp                      dirtyCardQueue.hpp
@@ -147,7 +143,6 @@ g1CollectedHeap.cpp                     g1RemSet.inline.hpp
 g1CollectedHeap.cpp                     g1OopClosures.inline.hpp
 g1CollectedHeap.cpp                     genOopClosures.inline.hpp
 g1CollectedHeap.cpp                     gcLocker.inline.hpp
-g1CollectedHeap.cpp                     gcOverheadReporter.hpp
 g1CollectedHeap.cpp                     generationSpec.hpp
 g1CollectedHeap.cpp                     heapRegionRemSet.hpp
 g1CollectedHeap.cpp                     heapRegionSeq.inline.hpp

src/share/vm/gc_implementation/includeDB_gc_shared

@@ -35,12 +35,6 @@ concurrentGCThread.cpp                  systemDictionary.hpp
 
 concurrentGCThread.hpp                  thread.hpp
 
-coTracker.hpp                           globalDefinitions.hpp
-coTracker.hpp                           numberSeq.hpp
-
-coTracker.cpp                           coTracker.hpp
-coTracker.cpp                           os.hpp
-
 allocationStats.cpp                     allocationStats.hpp
 allocationStats.cpp                     ostream.hpp
 
@@ -54,13 +48,6 @@ gcAdaptivePolicyCounters.hpp            gcPolicyCounters.hpp
 gcAdaptivePolicyCounters.cpp            resourceArea.hpp
 gcAdaptivePolicyCounters.cpp            gcAdaptivePolicyCounters.hpp
 
-gcOverheadReporter.cpp                  allocation.inline.hpp
-gcOverheadReporter.cpp                  concurrentGCThread.hpp
-gcOverheadReporter.cpp                  coTracker.hpp
-gcOverheadReporter.cpp                  gcOverheadReporter.hpp
-gcOverheadReporter.cpp                  ostream.hpp
-gcOverheadReporter.cpp                  thread_<os_family>.inline.hpp
-
 gSpaceCounters.cpp                      generation.hpp
 gSpaceCounters.cpp                      resourceArea.hpp
 gSpaceCounters.cpp                      gSpaceCounters.hpp

src/share/vm/gc_implementation/shared/coTracker.cpp

-/*
- * Copyright 2001-2007 Sun Microsystems, Inc.  All Rights Reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
- *
- */
-
-# include "incls/_precompiled.incl"
-# include "incls/_coTracker.cpp.incl"
-
-COTracker* COTracker::_head = NULL;
-double COTracker::_cpu_number = -1.0;
-
-void
-COTracker::resetPeriod(double now_sec, double vnow_sec) {
-  guarantee( _enabled, "invariant" );
-  _period_start_time_sec  = now_sec;
-  _period_start_vtime_sec = vnow_sec;
-}
-
-void
-COTracker::setConcOverhead(double time_stamp_sec,
-                           double conc_overhead) {
-  guarantee( _enabled, "invariant" );
-  _conc_overhead  = conc_overhead;
-  _time_stamp_sec = time_stamp_sec;
-  if (conc_overhead > 0.001)
-    _conc_overhead_seq.add(conc_overhead);
-}
-
-void
-COTracker::reset(double starting_conc_overhead) {
-  guarantee( _enabled, "invariant" );
-  double now_sec = os::elapsedTime();
-  setConcOverhead(now_sec, starting_conc_overhead);
-}
-
-void
-COTracker::start() {
-  guarantee( _enabled, "invariant" );
-  resetPeriod(os::elapsedTime(), os::elapsedVTime());
-}
-
-void
-COTracker::update(bool force_end) {
-  assert( _enabled, "invariant" );
-  double end_time_sec = os::elapsedTime();
-  double elapsed_time_sec = end_time_sec - _period_start_time_sec;
-  if (force_end || elapsed_time_sec > _update_period_sec) {
-    // reached the end of the period
-    double end_vtime_sec = os::elapsedVTime();
-    double elapsed_vtime_sec = end_vtime_sec - _period_start_vtime_sec;
-
-    double conc_overhead = elapsed_vtime_sec / elapsed_time_sec;
-
-    setConcOverhead(end_time_sec, conc_overhead);
-    resetPeriod(end_time_sec, end_vtime_sec);
-  }
-}
-
-void
-COTracker::updateForSTW(double start_sec, double end_sec) {
-  if (!_enabled)
-    return;
-
-  // During a STW pause, no concurrent GC thread has done any
-  // work. So, we can safely adjust the start of the current period by
-  // adding the duration of the STW pause to it, so that the STW pause
-  // doesn't affect the reading of the concurrent overhead (it's
-  // basically like excluding the time of the STW pause from the
-  // concurrent overhead calculation).
-
-  double stw_duration_sec = end_sec - start_sec;
-  guarantee( stw_duration_sec > 0.0, "invariant" );
-
-  if (outOfDate(start_sec))
-    _conc_overhead = 0.0;
-  else
-    _time_stamp_sec = end_sec;
-  _period_start_time_sec += stw_duration_sec;
-  _conc_overhead_seq = NumberSeq();
-
-  guarantee( os::elapsedTime() > _period_start_time_sec, "invariant" );
-}
-
-double
-COTracker::predConcOverhead() {
-  if (_enabled) {
-    // tty->print(" %1.2lf", _conc_overhead_seq.maximum());
-    return _conc_overhead_seq.maximum();
-  } else {
-    // tty->print(" DD");
-    return 0.0;
-  }
-}
-
-void
-COTracker::resetPred() {
-  _conc_overhead_seq = NumberSeq();
-}
-
-COTracker::COTracker(int group)
-    : _enabled(false),
-      _group(group),
-      _period_start_time_sec(-1.0),
-      _period_start_vtime_sec(-1.0),
-      _conc_overhead(-1.0),
-      _time_stamp_sec(-1.0),
-      _next(NULL) {
-  // GCOverheadReportingPeriodMS indicates how frequently the
-  // concurrent overhead will be recorded by the GC Overhead
-  // Reporter. We want to take readings less often than that. If we
-  // took readings more often than some of them might be lost.
-  _update_period_sec = ((double) GCOverheadReportingPeriodMS) / 1000.0 * 1.25;
-  _next = _head;
-  _head = this;
-
-  if (_cpu_number < 0.0)
-    _cpu_number = (double) os::processor_count();
-}
-
-// statics
-
-void
-COTracker::updateAllForSTW(double start_sec, double end_sec) {
-  for (COTracker* curr = _head; curr != NULL; curr = curr->_next) {
-    curr->updateForSTW(start_sec, end_sec);
-  }
-}
-
-double
-COTracker::totalConcOverhead(double now_sec) {
-  double total_conc_overhead = 0.0;
-
-  for (COTracker* curr = _head; curr != NULL; curr = curr->_next) {
-    double conc_overhead = curr->concOverhead(now_sec);
-    total_conc_overhead += conc_overhead;
-  }
-
-  return total_conc_overhead;
-}
-
-double
-COTracker::totalConcOverhead(double now_sec,
-                             size_t group_num,
-                             double* co_per_group) {
-  double total_conc_overhead = 0.0;
-
-  for (size_t i = 0; i < group_num; ++i)
-    co_per_group[i] = 0.0;
-
-  for (COTracker* curr = _head; curr != NULL; curr = curr->_next) {
-    size_t group = curr->_group;
-    assert( 0 <= group && group < group_num, "invariant" );
-    double conc_overhead = curr->concOverhead(now_sec);
-
-    co_per_group[group] += conc_overhead;
-    total_conc_overhead += conc_overhead;
-  }
-
-  return total_conc_overhead;
-}
-
-double
-COTracker::totalPredConcOverhead() {
-  double total_pred_conc_overhead = 0.0;
-  for (COTracker* curr = _head; curr != NULL; curr = curr->_next) {
-    total_pred_conc_overhead += curr->predConcOverhead();
-    curr->resetPred();
-  }
-  return total_pred_conc_overhead / _cpu_number;
-}

src/share/vm/gc_implementation/shared/coTracker.hpp

-/*
- * Copyright 2001-2007 Sun Microsystems, Inc.  All Rights Reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
- *
- */
-
-// COTracker keeps track of the concurrent overhead of a GC thread.
-
-// A thread that needs to be tracked must, itself, start up its
-// tracker with the start() method and then call the update() method
-// at regular intervals. What the tracker does is to calculate the
-// concurrent overhead of a process at a given update period. The
-// tracker starts and when is detects that it has exceeded the given
-// period, it calculates the duration of the period in wall-clock time
-// and the duration of the period in vtime (i.e. how much time the
-// concurrent processes really took up during this period). The ratio
-// of the latter over the former is the concurrent overhead of that
-// process for that period over a single CPU. This overhead is stored
-// on the tracker, "timestamped" with the wall-clock time of the end
-// of the period. When the concurrent overhead of this process needs
-// to be queried, this last "reading" provides a good approximation
-// (we assume that the concurrent overhead of a particular thread
-// stays largely constant over time). The timestamp is necessary to
-// detect when the process has stopped working and the recorded
-// reading hasn't been updated for some time.
-
-// Each concurrent GC thread is considered to be part of a "group"
-// (i.e. any available concurrent marking threads are part of the
-// "concurrent marking thread group"). A COTracker is associated with
-// a single group at construction-time. It's up to each collector to
-// decide how groups will be mapped to such an id (ids should start
-// from 0 and be consecutive; there's a hardcoded max group num
-// defined on the GCOverheadTracker class). The notion of a group has
-// been introduced to be able to identify how much overhead was
-// imposed by each group, instead of getting a single value that
-// covers all concurrent overhead.
-
-class COTracker {
-private:
-  // It indicates whether this tracker is enabled or not. When the
-  // tracker is disabled, then it returns 0.0 as the latest concurrent
-  // overhead and several methods (reset, start, and update) are not
-  // supposed to be called on it. This enabling / disabling facility
-  // is really provided to make a bit more explicit in the code when a
-  // particulary tracker of a processes that doesn't run all the time
-  // (e.g. concurrent marking) is supposed to be used and not it's not.
-  bool               _enabled;
-
-  // The ID of the group associated with this tracker.
-  int                _group;
-
-  // The update period of the tracker. A new value for the concurrent
-  // overhead of the associated process will be made at intervals no
-  // smaller than this.
-  double             _update_period_sec;
-
-  // The start times (both wall-block time and vtime) of the current
-  // interval.
-  double             _period_start_time_sec;
-  double             _period_start_vtime_sec;
-
-  // Number seq of the concurrent overhead readings within a period
-  NumberSeq          _conc_overhead_seq;
-
-  // The latest reading of the concurrent overhead (over a single CPU)
-  // imposed by the associated concurrent thread, made available at
-  // the indicated wall-clock time.
-  double             _conc_overhead;
-  double             _time_stamp_sec;
-
-  // The number of CPUs that the host machine has (for convenience
-  // really, as we'd have to keep translating it into a double)
-  static double      _cpu_number;
-
-  // Fields that keep a list of all trackers created. This is useful,
-  // since it allows us to sum up the concurrent overhead without
-  // having to write code for a specific collector to broadcast a
-  // request to all its concurrent processes.
-  COTracker*         _next;
-  static COTracker*  _head;
-
-  // It indicates that a new period is starting by updating the
-  // _period_start_time_sec and _period_start_vtime_sec fields.
-  void resetPeriod(double now_sec, double vnow_sec);
-  // It updates the latest concurrent overhead reading, taken at a
-  // given wall-clock time.
-  void setConcOverhead(double time_stamp_sec, double conc_overhead);
-
-  // It determines whether the time stamp of the latest concurrent
-  // overhead reading is out of date or not.
-  bool outOfDate(double now_sec) {
-    // The latest reading is considered out of date, if it was taken
-    // 1.2x the update period.
-    return (now_sec - _time_stamp_sec) > 1.2 * _update_period_sec;
-  }
-
-public:
-  // The constructor which associates the tracker with a group ID.
-  COTracker(int group);
-
-  // Methods to enable / disable the tracker and query whether it is enabled.
-  void enable()  { _enabled = true;  }
-  void disable() { _enabled = false; }
-  bool enabled() { return _enabled;  }
-
-  // It resets the tracker and sets concurrent overhead reading to be
-  // the given parameter and the associated time stamp to be now.
-  void reset(double starting_conc_overhead = 0.0);
-  // The tracker starts tracking. IT should only be called from the
-  // concurrent thread that is tracked by this tracker.
-  void start();
-  // It updates the tracker and, if the current period is longer than
-  // the update period, the concurrent overhead reading will be
-  // updated. force_end being true indicates that it's the last call
-  // to update() by this process before the tracker is disabled (the
-  // tracker can be re-enabled later if necessary).  It should only be
-  // called from the concurrent thread that is tracked by this tracker
-  // and while the thread has joined the STS.
-  void update(bool force_end = false);
-  // It adjusts the contents of the tracker to take into account a STW
-  // pause.
-  void updateForSTW(double start_sec, double end_sec);
-
-  // It returns the last concurrent overhead reading over a single
-  // CPU. If the reading is out of date, or the tracker is disabled,
-  // it returns 0.0.
-  double concCPUOverhead(double now_sec) {
-    if (!_enabled || outOfDate(now_sec))
-      return 0.0;
-    else
-      return _conc_overhead;
-  }
-
-  // It returns the last concurrent overhead reading over all CPUs
-  // that the host machine has. If the reading is out of date, or the
-  // tracker is disabled, it returns 0.0.
-  double concOverhead(double now_sec) {
-    return concCPUOverhead(now_sec) / _cpu_number;
-  }
-
-  double predConcOverhead();
-
-  void resetPred();
-
-  // statics
-
-  // It notifies all trackers about a STW pause.
-  static void updateAllForSTW(double start_sec, double end_sec);
-
-  // It returns the sum of the concurrent overhead readings of all
-  // available (and enabled) trackers for the given time stamp. The
-  // overhead is over all the CPUs of the host machine.
-
-  static double totalConcOverhead(double now_sec);
-  // Like the previous method, but it also sums up the overheads per
-  // group number. The length of the co_per_group array must be at
-  // least as large group_num
-  static double totalConcOverhead(double now_sec,
-                                  size_t group_num,
-                                  double* co_per_group);
-
-  static double totalPredConcOverhead();
-};

src/share/vm/gc_implementation/shared/gcOverheadReporter.cpp

-/*
- * Copyright 2001-2007 Sun Microsystems, Inc.  All Rights Reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
- *
- */
-
-# include "incls/_precompiled.incl"
-# include "incls/_gcOverheadReporter.cpp.incl"
-
-class COReportingThread : public ConcurrentGCThread {
-private:
-  GCOverheadReporter* _reporter;
-
-public:
-  COReportingThread(GCOverheadReporter* reporter) : _reporter(reporter) {
-    guarantee( _reporter != NULL, "precondition" );
-    create_and_start();
-  }
-
-  virtual void run() {
-    initialize_in_thread();
-    wait_for_universe_init();
-
-    int period_ms = GCOverheadReportingPeriodMS;
-
-    while ( true ) {
-      os::sleep(Thread::current(), period_ms, false);
-
-      _sts.join();
-      double now_sec = os::elapsedTime();
-      _reporter->collect_and_record_conc_overhead(now_sec);
-      _sts.leave();
-    }
-
-    terminate();
-  }
-};
-
-GCOverheadReporter* GCOverheadReporter::_reporter = NULL;
-
-GCOverheadReporter::GCOverheadReporter(size_t group_num,
-                                       const char* group_names[],
-                                       size_t length)
-    : _group_num(group_num), _prev_end_sec(0.0) {
-  guarantee( 0 <= group_num && group_num <= MaxGCOverheadGroupNum,
-             "precondition" );
-
-  _base = NEW_C_HEAP_ARRAY(GCOverheadReporterEntry, length);
-  _top  = _base + length;
-  _curr = _base;
-
-  for (size_t i = 0; i < group_num; ++i) {
-    guarantee( group_names[i] != NULL, "precondition" );
-    _group_names[i] = group_names[i];
-  }
-}
-
-void
-GCOverheadReporter::add(double start_sec, double end_sec,
-                        double* conc_overhead,
-                        double stw_overhead) {
-  assert( _curr <= _top, "invariant" );
-
-  if (_curr == _top) {
-    guarantee( false, "trace full" );
-    return;
-  }
-
-  _curr->_start_sec       = start_sec;
-  _curr->_end_sec         = end_sec;
-  for (size_t i = 0; i < _group_num; ++i) {
-    _curr->_conc_overhead[i] =
-      (conc_overhead != NULL) ? conc_overhead[i] : 0.0;
-  }
-  _curr->_stw_overhead    = stw_overhead;
-
-  ++_curr;
-}
-
-void
-GCOverheadReporter::collect_and_record_conc_overhead(double end_sec) {
-  double start_sec = _prev_end_sec;
-  guarantee( end_sec > start_sec, "invariant" );
-
-  double conc_overhead[MaxGCOverheadGroupNum];
-  COTracker::totalConcOverhead(end_sec, _group_num, conc_overhead);
-  add_conc_overhead(start_sec, end_sec, conc_overhead);
-  _prev_end_sec = end_sec;
-}
-
-void
-GCOverheadReporter::record_stw_start(double start_sec) {
-  guarantee( start_sec > _prev_end_sec, "invariant" );
-  collect_and_record_conc_overhead(start_sec);
-}
-
-void
-GCOverheadReporter::record_stw_end(double end_sec) {
-  double start_sec = _prev_end_sec;
-  COTracker::updateAllForSTW(start_sec, end_sec);
-  add_stw_overhead(start_sec, end_sec, 1.0);
-
-  _prev_end_sec = end_sec;
-}
-
-void
-GCOverheadReporter::print() const {
-  tty->print_cr("");
-  tty->print_cr("GC Overhead (%d entries)", _curr - _base);
-  tty->print_cr("");
-  GCOverheadReporterEntry* curr = _base;
-  while (curr < _curr) {
-    double total = curr->_stw_overhead;
-    for (size_t i = 0; i < _group_num; ++i)
-      total += curr->_conc_overhead[i];
-
-    tty->print("OVERHEAD %12.8lf %12.8lf ",
-               curr->_start_sec, curr->_end_sec);
-
-    for (size_t i = 0; i < _group_num; ++i)
-      tty->print("%s %12.8lf ", _group_names[i], curr->_conc_overhead[i]);
-
-    tty->print_cr("STW %12.8lf TOT %12.8lf", curr->_stw_overhead, total);
-    ++curr;
-  }
-  tty->print_cr("");
-}
-
-// statics
-
-void
-GCOverheadReporter::initGCOverheadReporter(size_t group_num,
-                                           const char* group_names[]) {
-  guarantee( _reporter == NULL, "should only be called once" );
-  guarantee( 0 <= group_num && group_num <= MaxGCOverheadGroupNum,
-             "precondition" );
-  guarantee( group_names != NULL, "pre-condition" );
-
-  if (GCOverheadReporting) {
-    _reporter = new GCOverheadReporter(group_num, group_names);
-    new COReportingThread(_reporter);
-  }
-}
-
-void
-GCOverheadReporter::recordSTWStart(double start_sec) {
-  if (_reporter != NULL)
-    _reporter->record_stw_start(start_sec);
-}
-
-void
-GCOverheadReporter::recordSTWEnd(double end_sec) {
-  if (_reporter != NULL)
-    _reporter->record_stw_end(end_sec);
-}
-
-void
-GCOverheadReporter::printGCOverhead() {
-  if (_reporter != NULL)
-    _reporter->print();
-}

src/share/vm/gc_implementation/shared/gcOverheadReporter.hpp

-/*
- * Copyright 2001-2007 Sun Microsystems, Inc.  All Rights Reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
- *
- */
-
-// Keeps track of the GC overhead (both concurrent and STW). It stores
-// it in a large array and then prints it to tty at the end of the
-// execution.
-
-// See coTracker.hpp for the explanation on what groups are.
-
-// Let's set a maximum number of concurrent overhead groups, to
-// statically allocate any arrays we need and not to have to
-// malloc/free them. This is just a bit more convenient.
-enum {
-  MaxGCOverheadGroupNum = 4
-};
-
-typedef struct {
-  double _start_sec;
-  double _end_sec;
-
-  double _conc_overhead[MaxGCOverheadGroupNum];
-  double _stw_overhead;
-} GCOverheadReporterEntry;
-
-class GCOverheadReporter {
-  friend class COReportingThread;
-
-private:
-  enum PrivateConstants {
-    DefaultReporterLength = 128 * 1024
-  };
-
-  // Reference to the single instance of this class.
-  static GCOverheadReporter* _reporter;
-
-  // These three references point to the array that contains the GC
-  // overhead entries (_base is the base of the array, _top is the
-  // address passed the last entry of the array, _curr is the next
-  // entry to be used).
-  GCOverheadReporterEntry* _base;
-  GCOverheadReporterEntry* _top;
-  GCOverheadReporterEntry* _curr;
-
-  // The number of concurrent overhead groups.
-  size_t _group_num;
-
-  // The wall-clock time of the end of the last recorded period of GC
-  // overhead.
-  double _prev_end_sec;
-
-  // Names for the concurrent overhead groups.
-  const char* _group_names[MaxGCOverheadGroupNum];
-
-  // Add a new entry to the large array. conc_overhead being NULL is
-  // equivalent to an array full of 0.0s. conc_overhead should have a
-  // length of at least _group_num.
-  void add(double start_sec, double end_sec,
-           double* conc_overhead,
-           double stw_overhead);
-
-  // Add an entry that represents concurrent GC overhead.
-  // conc_overhead must be at least of length _group_num.
-  // conc_overhead being NULL is equivalent to an array full of 0.0s.
-  void add_conc_overhead(double start_sec, double end_sec,
-                         double* conc_overhead) {
-    add(start_sec, end_sec, conc_overhead, 0.0);
-  }
-
-  // Add an entry that represents STW GC overhead.
-  void add_stw_overhead(double start_sec, double end_sec,
-                        double stw_overhead) {
-    add(start_sec, end_sec, NULL, stw_overhead);
-  }
-
-  // It records the start of a STW pause (i.e. it records the
-  // concurrent overhead up to that point)
-  void record_stw_start(double start_sec);
-
-  // It records the end of a STW pause (i.e. it records the overhead
-  // associated with the pause and adjusts all the trackers to reflect
-  // the pause)
-  void record_stw_end(double end_sec);
-
-  // It queries all the trackers of their concurrent overhead and
-  // records it.
-  void collect_and_record_conc_overhead(double end_sec);
-
-  // It prints the contents of the GC overhead array
-  void print() const;
-
-
-  // Constructor. The same preconditions for group_num and group_names
-  // from initGCOverheadReporter apply here too.
-  GCOverheadReporter(size_t group_num,
-                     const char* group_names[],
-                     size_t length = DefaultReporterLength);
-
-public:
-
-  // statics
-
-  // It initialises the GCOverheadReporter and launches the concurrent
-  // overhead reporting thread. Both actions happen only if the
-  // GCOverheadReporting parameter is set. The length of the
-  // group_names array should be >= group_num and group_num should be
-  // <= MaxGCOverheadGroupNum. Entries group_namnes[0..group_num-1]
-  // should not be NULL.
-  static void initGCOverheadReporter(size_t group_num,
-                                     const char* group_names[]);
-
-  // The following three are provided for convenience and they are
-  // wrappers around record_stw_start(start_sec), record_stw_end(end_sec),
-  // and print(). Each of these checks whether GC overhead reporting
-  // is on (i.e. _reporter != NULL) and, if it is, calls the
-  // corresponding method. Saves from repeating this pattern again and
-  // again from the places where they need to be called.
-  static void recordSTWStart(double start_sec);
-  static void recordSTWEnd(double end_sec);
-  static void printGCOverhead();
-};