src/hotspot/share/gc/g1/g1GCPhaseTimes.cpp

/*
 * Copyright (c) 2013, 2025, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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#include "gc/g1/g1CollectedHeap.inline.hpp"
#include "gc/g1/g1GCParPhaseTimesTracker.hpp"
#include "gc/g1/g1GCPhaseTimes.hpp"
#include "gc/g1/g1ParScanThreadState.inline.hpp"
#include "gc/shared/gcTimer.hpp"
#include "gc/shared/oopStorage.hpp"
#include "gc/shared/oopStorageSet.hpp"
#include "gc/shared/tlab_globals.hpp"
#include "gc/shared/workerDataArray.inline.hpp"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "memory/resourceArea.hpp"
#include "runtime/os.hpp"
#include "runtime/timer.hpp"
#include "utilities/enumIterator.hpp"
#include "utilities/macros.hpp"

constexpr const char* G1GCPhaseTimes::GCMergeRSWorkItemsStrings[];

G1GCPhaseTimes::G1GCPhaseTimes(STWGCTimer* gc_timer, uint max_gc_threads) :
  _max_gc_threads(max_gc_threads),
  _gc_start_counter(0),
  _gc_pause_time_ms(0.0),
  _ref_phase_times(gc_timer, max_gc_threads),
  _weak_phase_times(max_gc_threads)
{
  assert(max_gc_threads > 0, "Must have some GC threads");

  _gc_par_phases[RetireTLABsAndFlushLogs] = new WorkerDataArray<double>("RetireTLABsAndFlushLogs", "JT Retire TLABs And Flush Logs (ms):", max_gc_threads);
  _gc_par_phases[NonJavaThreadFlushLogs] = new WorkerDataArray<double>("NonJavaThreadFlushLogs", "Non-JT Flush Logs (ms):", max_gc_threads);

  _gc_par_phases[GCWorkerStart] = new WorkerDataArray<double>("GCWorkerStart", "GC Worker Start (ms):", max_gc_threads);
  _gc_par_phases[ExtRootScan] = new WorkerDataArray<double>("ExtRootScan", "Ext Root Scanning (ms):", max_gc_threads);

  // Root scanning phases
  _gc_par_phases[ThreadRoots] = new WorkerDataArray<double>("ThreadRoots", "Thread Roots (ms):", max_gc_threads);
  _gc_par_phases[CLDGRoots] = new WorkerDataArray<double>("CLDGRoots", "CLDG Roots (ms):", max_gc_threads);
  _gc_par_phases[CMRefRoots] = new WorkerDataArray<double>("CMRefRoots", "CM RefProcessor Roots (ms):", max_gc_threads);

  for (auto id : EnumRange<OopStorageSet::StrongId>()) {
    GCParPhases phase = strong_oopstorage_phase(id);
    const char* phase_name_postfix = " Roots (ms):";
    const char* storage_name = OopStorageSet::storage(id)->name();
    char* oop_storage_phase_name = NEW_C_HEAP_ARRAY(char, strlen(phase_name_postfix) + strlen(storage_name) + 1, mtGC);
    strcpy(oop_storage_phase_name, storage_name);
    strcat(oop_storage_phase_name, phase_name_postfix);
    _gc_par_phases[phase] = new WorkerDataArray<double>(storage_name, oop_storage_phase_name, max_gc_threads);
  }

  _gc_par_phases[MergeER] = new WorkerDataArray<double>("MergeER", "Eager Reclaim (ms):", max_gc_threads);

  _gc_par_phases[MergeRS] = new WorkerDataArray<double>("MergeRS", "Remembered Sets (ms):", max_gc_threads);
  for (uint i = 0; i < MergeRSContainersSentinel; i++) {
    _gc_par_phases[MergeRS]->create_thread_work_items(GCMergeRSWorkItemsStrings[i], i);
  }

  _gc_par_phases[OptMergeRS] = new WorkerDataArray<double>("OptMergeRS", "Optional Remembered Sets (ms):", max_gc_threads);
  for (uint i = 0; i < MergeRSContainersSentinel; i++) {
    _gc_par_phases[OptMergeRS]->create_thread_work_items(GCMergeRSWorkItemsStrings[i], i);
  }

  _gc_par_phases[MergeLB] = new WorkerDataArray<double>("MergeLB", "Log Buffers (ms):", max_gc_threads);
  _gc_par_phases[ScanHR] = new WorkerDataArray<double>("ScanHR", "Scan Heap Roots (ms):", max_gc_threads);
  _gc_par_phases[OptScanHR] = new WorkerDataArray<double>("OptScanHR", "Optional Scan Heap Roots (ms):", max_gc_threads);
  _gc_par_phases[CodeRoots] = new WorkerDataArray<double>("CodeRoots", "Code Root Scan (ms):", max_gc_threads);
  _gc_par_phases[OptCodeRoots] = new WorkerDataArray<double>("OptCodeRoots", "Optional Code Root Scan (ms):", max_gc_threads);
  _gc_par_phases[ObjCopy] = new WorkerDataArray<double>("ObjCopy", "Object Copy (ms):", max_gc_threads);
  _gc_par_phases[OptObjCopy] = new WorkerDataArray<double>("OptObjCopy", "Optional Object Copy (ms):", max_gc_threads);
  _gc_par_phases[Termination] = new WorkerDataArray<double>("Termination", "Termination (ms):", max_gc_threads);
  _gc_par_phases[OptTermination] = new WorkerDataArray<double>("OptTermination", "Optional Termination (ms):", max_gc_threads);
  _gc_par_phases[GCWorkerTotal] = new WorkerDataArray<double>("GCWorkerTotal", "GC Worker Total (ms):", max_gc_threads);
  _gc_par_phases[GCWorkerEnd] = new WorkerDataArray<double>("GCWorkerEnd", "GC Worker End (ms):", max_gc_threads);
  _gc_par_phases[Other] = new WorkerDataArray<double>("Other", "GC Worker Other (ms):", max_gc_threads);
  _gc_par_phases[MergePSS] = new WorkerDataArray<double>("MergePSS", "Merge Per-Thread State (ms):", max_gc_threads);
  _gc_par_phases[RestoreEvacuationFailedRegions] = new WorkerDataArray<double>("RestoreEvacuationFailedRegions", "Restore Evacuation Failed Regions (ms):", max_gc_threads);
  _gc_par_phases[RemoveSelfForwards] = new WorkerDataArray<double>("RemoveSelfForwards", "Remove Self Forwards (ms):", max_gc_threads);
  _gc_par_phases[ClearCardTable] = new WorkerDataArray<double>("ClearLoggedCards", "Clear Logged Cards (ms):", max_gc_threads);
  _gc_par_phases[RecalculateUsed] = new WorkerDataArray<double>("RecalculateUsed", "Recalculate Used Memory (ms):", max_gc_threads);
#if COMPILER2_OR_JVMCI
  _gc_par_phases[UpdateDerivedPointers] = new WorkerDataArray<double>("UpdateDerivedPointers", "Update Derived Pointers (ms):", max_gc_threads);
#endif
  _gc_par_phases[EagerlyReclaimHumongousObjects] = new WorkerDataArray<double>("EagerlyReclaimHumongousObjects", "Eagerly Reclaim Humongous Objects (ms):", max_gc_threads);
  _gc_par_phases[ResetPartialArrayStateManager] = new WorkerDataArray<double>("ResetPartialArrayStateManager", "Reset Partial Array State Manager (ms):", max_gc_threads);
  _gc_par_phases[ProcessEvacuationFailedRegions] = new WorkerDataArray<double>("ProcessEvacuationFailedRegions", "Process Evacuation Failed Regions (ms):", max_gc_threads);

  _gc_par_phases[ScanHR]->create_thread_work_items("Scanned Cards:", ScanHRScannedCards);
  _gc_par_phases[ScanHR]->create_thread_work_items("Scanned Blocks:", ScanHRScannedBlocks);
  _gc_par_phases[ScanHR]->create_thread_work_items("Claimed Chunks:", ScanHRClaimedChunks);
  _gc_par_phases[ScanHR]->create_thread_work_items("Found Roots:", ScanHRFoundRoots);

  _gc_par_phases[OptScanHR]->create_thread_work_items("Scanned Cards:", ScanHRScannedCards);
  _gc_par_phases[OptScanHR]->create_thread_work_items("Scanned Blocks:", ScanHRScannedBlocks);
  _gc_par_phases[OptScanHR]->create_thread_work_items("Claimed Chunks:", ScanHRClaimedChunks);
  _gc_par_phases[OptScanHR]->create_thread_work_items("Found Roots:", ScanHRFoundRoots);
  _gc_par_phases[OptScanHR]->create_thread_work_items("Scanned Refs:", ScanHRScannedOptRefs);
  _gc_par_phases[OptScanHR]->create_thread_work_items("Used Memory:", ScanHRUsedMemory);

  _gc_par_phases[MergeLB]->create_thread_work_items("Dirty Cards:", MergeLBDirtyCards);
  _gc_par_phases[MergeLB]->create_thread_work_items("Skipped Cards:", MergeLBSkippedCards);

  _gc_par_phases[CodeRoots]->create_thread_work_items("Scanned Nmethods:", CodeRootsScannedNMethods);

  _gc_par_phases[OptCodeRoots]->create_thread_work_items("Scanned Nmethods:", CodeRootsScannedNMethods);

  _gc_par_phases[MergePSS]->create_thread_work_items("Copied Bytes:", MergePSSCopiedBytes);
  _gc_par_phases[MergePSS]->create_thread_work_items("LAB Waste:", MergePSSLABWasteBytes);
  _gc_par_phases[MergePSS]->create_thread_work_items("LAB Undo Waste:", MergePSSLABUndoWasteBytes);
  _gc_par_phases[MergePSS]->create_thread_work_items("Evac Fail Extra Cards:", MergePSSEvacFailExtra);

  _gc_par_phases[RestoreEvacuationFailedRegions]->create_thread_work_items("Evacuation Failed Regions:", RestoreEvacFailureRegionsEvacFailedNum);
  _gc_par_phases[RestoreEvacuationFailedRegions]->create_thread_work_items("Pinned Regions:", RestoreEvacFailureRegionsPinnedNum);
  _gc_par_phases[RestoreEvacuationFailedRegions]->create_thread_work_items("Allocation Failed Regions:", RestoreEvacFailureRegionsAllocFailedNum);

  _gc_par_phases[RemoveSelfForwards]->create_thread_work_items("Forward Chunks:", RemoveSelfForwardChunksNum);
  _gc_par_phases[RemoveSelfForwards]->create_thread_work_items("Empty Forward Chunks:", RemoveSelfForwardEmptyChunksNum);
  _gc_par_phases[RemoveSelfForwards]->create_thread_work_items("Forward Objects:", RemoveSelfForwardObjectsNum);
  _gc_par_phases[RemoveSelfForwards]->create_thread_work_items("Forward Bytes:", RemoveSelfForwardObjectsBytes);

  _gc_par_phases[EagerlyReclaimHumongousObjects]->create_thread_work_items("Humongous Total:", EagerlyReclaimNumTotal);
  _gc_par_phases[EagerlyReclaimHumongousObjects]->create_thread_work_items("Humongous Candidates:", EagerlyReclaimNumCandidates);
  _gc_par_phases[EagerlyReclaimHumongousObjects]->create_thread_work_items("Humongous Reclaimed:", EagerlyReclaimNumReclaimed);

  _gc_par_phases[SampleCollectionSetCandidates] = new WorkerDataArray<double>("SampleCandidates", "Sample CSet Candidates (ms):", max_gc_threads);

  _gc_par_phases[Termination]->create_thread_work_items("Termination Attempts:");

  _gc_par_phases[OptTermination]->create_thread_work_items("Optional Termination Attempts:");

  _gc_par_phases[RedirtyCards] = new WorkerDataArray<double>("RedirtyCards", "Redirty Logged Cards (ms):", max_gc_threads);
  _gc_par_phases[RedirtyCards]->create_thread_work_items("Redirtied Cards:");

  _gc_par_phases[ResizeThreadLABs] = new WorkerDataArray<double>("ResizeTLABs", "Resize TLABs (ms):", max_gc_threads);

  _gc_par_phases[FreeCollectionSet] = new WorkerDataArray<double>("FreeCSet", "Free Collection Set (ms):", max_gc_threads);
  _gc_par_phases[YoungFreeCSet] = new WorkerDataArray<double>("YoungFreeCSet", "Young Free Collection Set (ms):", max_gc_threads);
  _gc_par_phases[NonYoungFreeCSet] = new WorkerDataArray<double>("NonYoungFreeCSet", "Non-Young Free Collection Set (ms):", max_gc_threads);
  _gc_par_phases[RebuildFreeList] = new WorkerDataArray<double>("RebuildFreeList", "Parallel Rebuild Free List (ms):", max_gc_threads);

  _gc_par_phases[ResetMarkingState] = new WorkerDataArray<double>("ResetMarkingState", "Reset Marking State (ms):", max_gc_threads);
  _gc_par_phases[NoteStartOfMark] = new WorkerDataArray<double>("NoteStartOfMark", "Note Start Of Mark (ms):", max_gc_threads);

  reset();
}

void G1GCPhaseTimes::reset() {
  _cur_collection_initial_evac_time_ms = 0.0;
  _cur_optional_evac_time_ms = 0.0;
  _cur_collection_nmethod_list_cleanup_time_ms = 0.0;
  _cur_merge_heap_roots_time_ms = 0.0;
  _cur_optional_merge_heap_roots_time_ms = 0.0;
  _cur_prepare_merge_heap_roots_time_ms = 0.0;
  _cur_distribute_log_buffers_time_ms = 0.0;
  _cur_optional_prepare_merge_heap_roots_time_ms = 0.0;
  _cur_pre_evacuate_prepare_time_ms = 0.0;
  _cur_post_evacuate_cleanup_1_time_ms = 0.0;
  _cur_post_evacuate_cleanup_2_time_ms = 0.0;
  _cur_expand_heap_time_ms = 0.0;
  _cur_ref_proc_time_ms = 0.0;
  _cur_collection_start_sec = 0.0;
  _root_region_scan_wait_time_ms = 0.0;
  _external_accounted_time_ms = 0.0;
  _recorded_prepare_heap_roots_time_ms = 0.0;
  _recorded_young_cset_choice_time_ms = 0.0;
  _recorded_non_young_cset_choice_time_ms = 0.0;
  _recorded_prepare_for_mutator_time_ms = 0.0;
  _recorded_serial_free_cset_time_ms = 0.0;
  _recorded_total_rebuild_freelist_time_ms = 0.0;
  _recorded_serial_rebuild_freelist_time_ms = 0.0;
  _cur_region_register_time = 0.0;
  _cur_verify_before_time_ms = 0.0;
  _cur_verify_after_time_ms = 0.0;
  _cur_prepare_concurrent_task_time_ms = 0.0;

  for (int i = 0; i < GCParPhasesSentinel; i++) {
    if (_gc_par_phases[i] != nullptr) {
      _gc_par_phases[i]->reset();
    }
  }

  _ref_phase_times.reset();
  _weak_phase_times.reset();
}

void G1GCPhaseTimes::record_gc_pause_start() {
  _gc_start_counter = os::elapsed_counter();
  reset();
}

#define ASSERT_PHASE_UNINITIALIZED(phase) \
    assert(_gc_par_phases[phase] == nullptr || _gc_par_phases[phase]->get(i) == uninitialized, "Phase " #phase " reported for thread that was not started");

double G1GCPhaseTimes::worker_time(GCParPhases phase, uint worker) {
  if (_gc_par_phases[phase] == nullptr) {
    return 0.0;
  }
  double value = _gc_par_phases[phase]->get(worker);
  if (value != WorkerDataArray<double>::uninitialized()) {
    return value;
  }
  return 0.0;
}

void G1GCPhaseTimes::record_gc_pause_end() {
  _gc_pause_time_ms = TimeHelper::counter_to_millis(os::elapsed_counter() - _gc_start_counter);

  double uninitialized = WorkerDataArray<double>::uninitialized();

  for (uint i = 0; i < _max_gc_threads; i++) {
    double worker_start = _gc_par_phases[GCWorkerStart]->get(i);
    if (worker_start != uninitialized) {
      assert(_gc_par_phases[GCWorkerEnd]->get(i) != uninitialized, "Worker started but not ended.");
      double total_worker_time = _gc_par_phases[GCWorkerEnd]->get(i) - _gc_par_phases[GCWorkerStart]->get(i);
      record_time_secs(GCWorkerTotal, i , total_worker_time);

      double worker_known_time = worker_time(ExtRootScan, i) +
                                 worker_time(ScanHR, i) +
                                 worker_time(CodeRoots, i) +
                                 worker_time(ObjCopy, i) +
                                 worker_time(Termination, i);

      record_time_secs(Other, i, total_worker_time - worker_known_time);
    } else {
      // Make sure all slots are uninitialized since this thread did not seem to have been started
      ASSERT_PHASE_UNINITIALIZED(GCWorkerEnd);
      ASSERT_PHASE_UNINITIALIZED(ExtRootScan);
      ASSERT_PHASE_UNINITIALIZED(MergeER);
      ASSERT_PHASE_UNINITIALIZED(MergeRS);
      ASSERT_PHASE_UNINITIALIZED(OptMergeRS);
      ASSERT_PHASE_UNINITIALIZED(MergeLB);
      ASSERT_PHASE_UNINITIALIZED(ScanHR);
      ASSERT_PHASE_UNINITIALIZED(CodeRoots);
      ASSERT_PHASE_UNINITIALIZED(OptCodeRoots);
      ASSERT_PHASE_UNINITIALIZED(ObjCopy);
      ASSERT_PHASE_UNINITIALIZED(OptObjCopy);
      ASSERT_PHASE_UNINITIALIZED(Termination);
    }
  }
}

#undef ASSERT_PHASE_UNINITIALIZED

// record the time a phase took in seconds
void G1GCPhaseTimes::record_time_secs(GCParPhases phase, uint worker_id, double secs) {
  _gc_par_phases[phase]->set(worker_id, secs);
}

// add a number of seconds to a phase
void G1GCPhaseTimes::add_time_secs(GCParPhases phase, uint worker_id, double secs) {
  _gc_par_phases[phase]->add(worker_id, secs);
}

void G1GCPhaseTimes::record_or_add_time_secs(GCParPhases phase, uint worker_id, double secs) {
  _gc_par_phases[phase]->set_or_add(worker_id, secs);
}

double G1GCPhaseTimes::get_time_secs(GCParPhases phase, uint worker_id) {
  return _gc_par_phases[phase]->get(worker_id);
}

void G1GCPhaseTimes::record_thread_work_item(GCParPhases phase, uint worker_id, size_t count, uint index) {
  _gc_par_phases[phase]->set_thread_work_item(worker_id, count, index);
}

void G1GCPhaseTimes::record_or_add_thread_work_item(GCParPhases phase, uint worker_id, size_t count, uint index) {
  _gc_par_phases[phase]->set_or_add_thread_work_item(worker_id, count, index);
}

size_t G1GCPhaseTimes::get_thread_work_item(GCParPhases phase, uint worker_id, uint index) {
  return _gc_par_phases[phase]->get_thread_work_item(worker_id, index);
}

// return the average time for a phase in milliseconds
double G1GCPhaseTimes::average_time_ms(GCParPhases phase) const {
  if (_gc_par_phases[phase] == nullptr) {
    return 0.0;
  }
  return _gc_par_phases[phase]->average() * 1000.0;
}

size_t G1GCPhaseTimes::sum_thread_work_items(GCParPhases phase, uint index) {
  if (_gc_par_phases[phase] == nullptr) {
    return 0;
  }
  assert(_gc_par_phases[phase]->thread_work_items(index) != nullptr, "No sub count");
  return _gc_par_phases[phase]->thread_work_items(index)->sum();
}

template <class T>
void G1GCPhaseTimes::details(T* phase, uint indent_level) const {
  LogTarget(Trace, gc, phases, task) lt;
  if (lt.is_enabled()) {
    LogStream ls(lt);
    ls.sp(indent_level * 2);
    phase->print_details_on(&ls);
  }
}

void G1GCPhaseTimes::print_thread_work_items(WorkerDataArray<double>* phase, uint indent_level, outputStream* out) const {
  for (uint i = 0; i < phase->MaxThreadWorkItems; i++) {
    WorkerDataArray<size_t>* work_items = phase->thread_work_items(i);
    if (work_items != nullptr) {
      out->sp((indent_level + 1) * 2);
      work_items->print_summary_on(out, true);
      details(work_items, indent_level + 1);
    }
  }
}

void G1GCPhaseTimes::debug_phase_merge_remset() const {
  LogTarget(Debug, gc, phases) lt;
  if (!lt.is_enabled()) {
    return;
  }

  LogStream ls(lt);

  WorkerDataArray<double>* phase = _gc_par_phases[MergeRS];
  WorkerDataArray<double>* sub_phase = _gc_par_phases[MergeER];

  uint indent_level = 2;

  ls.sp(indent_level * 2);
  phase->print_summary_on(&ls, true);
  details(phase, indent_level);

  log_phase(sub_phase, (indent_level + 1), &ls, true);

  print_thread_work_items(phase, indent_level, &ls);
}

void G1GCPhaseTimes::log_phase(WorkerDataArray<double>* phase, uint indent_level, outputStream* out, bool print_sum) const {
  out->sp(indent_level * 2);
  phase->print_summary_on(out, print_sum);
  details(phase, indent_level);

  print_thread_work_items(phase, indent_level, out);
}

void G1GCPhaseTimes::debug_phase(WorkerDataArray<double>* phase, uint extra_indent) const {
  LogTarget(Debug, gc, phases) lt;
  if (lt.is_enabled()) {
    LogStream ls(lt);
    log_phase(phase, 2 + extra_indent, &ls, true);
  }
}

void G1GCPhaseTimes::trace_phase(WorkerDataArray<double>* phase, bool print_sum, uint extra_indent) const {
  LogTarget(Trace, gc, phases) lt;
  if (lt.is_enabled()) {
    LogStream ls(lt);
    log_phase(phase, 3 + extra_indent, &ls, print_sum);
  }
}

#define TIME_FORMAT "%.2lfms"

void G1GCPhaseTimes::info_time(const char* name, double value) const {
  log_info(gc, phases)("  %s: " TIME_FORMAT, name, value);
}

void G1GCPhaseTimes::debug_time(const char* name, double value) const {
  log_debug(gc, phases)("    %s: " TIME_FORMAT, name, value);
}

void G1GCPhaseTimes::debug_time_for_reference(const char* name, double value) const {
  LogTarget(Debug, gc, phases) lt;
  LogTarget(Debug, gc, phases, ref) lt2;

  if (lt.is_enabled()) {
    LogStream ls(lt);
    ls.print_cr("    %s: " TIME_FORMAT, name, value);
  } else if (lt2.is_enabled()) {
    LogStream ls(lt2);
    ls.print_cr("    %s: " TIME_FORMAT, name, value);
  }
}

void G1GCPhaseTimes::trace_time(const char* name, double value) const {
  log_trace(gc, phases)("      %s: " TIME_FORMAT, name, value);
}

void G1GCPhaseTimes::trace_count(const char* name, size_t value) const {
  log_trace(gc, phases)("      %s: %zu", name, value);
}

double G1GCPhaseTimes::print_pre_evacuate_collection_set() const {
  const double sum_ms = _cur_prepare_concurrent_task_time_ms +
                        _cur_pre_evacuate_prepare_time_ms +
                        _recorded_young_cset_choice_time_ms +
                        _recorded_non_young_cset_choice_time_ms +
                        _cur_region_register_time +
                        _recorded_prepare_heap_roots_time_ms;

  info_time("Pre Evacuate Collection Set", sum_ms);

  // Concurrent tasks of ResetMarkingState and NoteStartOfMark are triggered during
  // young collection. However, their execution time are not included in _gc_pause_time_ms.
  if (_cur_prepare_concurrent_task_time_ms > 0.0) {
    debug_time("Prepare Concurrent Start", _cur_prepare_concurrent_task_time_ms);
    debug_phase(_gc_par_phases[ResetMarkingState], 1);
    debug_phase(_gc_par_phases[NoteStartOfMark], 1);
  }

  debug_time("Pre Evacuate Prepare", _cur_pre_evacuate_prepare_time_ms);
  debug_phase(_gc_par_phases[RetireTLABsAndFlushLogs], 1);
  debug_phase(_gc_par_phases[NonJavaThreadFlushLogs], 1);
  debug_time("Choose Collection Set", (_recorded_young_cset_choice_time_ms + _recorded_non_young_cset_choice_time_ms));
  debug_time("Region Register", _cur_region_register_time);

  debug_time("Prepare Heap Roots", _recorded_prepare_heap_roots_time_ms);

  return sum_ms;
}

double G1GCPhaseTimes::print_evacuate_optional_collection_set() const {
  const double sum_ms = _cur_optional_evac_time_ms + _cur_optional_merge_heap_roots_time_ms;
  if (sum_ms > 0) {
    info_time("Merge Optional Heap Roots", _cur_optional_merge_heap_roots_time_ms);

    debug_time("Prepare Optional Merge Heap Roots", _cur_optional_prepare_merge_heap_roots_time_ms);
    debug_phase(_gc_par_phases[OptMergeRS]);

    info_time("Evacuate Optional Collection Set", _cur_optional_evac_time_ms);
    debug_phase(_gc_par_phases[OptScanHR]);
    debug_phase(_gc_par_phases[OptObjCopy]);
    debug_phase(_gc_par_phases[OptCodeRoots]);
    debug_phase(_gc_par_phases[OptTermination]);
  }
  return sum_ms;
}

double G1GCPhaseTimes::print_evacuate_initial_collection_set() const {
  info_time("Merge Heap Roots", _cur_merge_heap_roots_time_ms);

  debug_time("Prepare Merge Heap Roots", _cur_prepare_merge_heap_roots_time_ms);
  debug_phase_merge_remset();

  debug_time("Distribute Log Buffers", _cur_distribute_log_buffers_time_ms);
  debug_phase(_gc_par_phases[MergeLB]);

  info_time("Evacuate Collection Set", _cur_collection_initial_evac_time_ms);

  trace_phase(_gc_par_phases[GCWorkerStart], false);
  debug_phase(_gc_par_phases[ExtRootScan]);
  for (int i = ExtRootScanSubPhasesFirst; i <= ExtRootScanSubPhasesLast; i++) {
    trace_phase(_gc_par_phases[i]);
  }
  debug_phase(_gc_par_phases[ScanHR]);
  debug_phase(_gc_par_phases[CodeRoots]);
  debug_phase(_gc_par_phases[ObjCopy]);
  debug_phase(_gc_par_phases[Termination]);
  debug_phase(_gc_par_phases[Other]);
  debug_phase(_gc_par_phases[GCWorkerTotal]);
  trace_phase(_gc_par_phases[GCWorkerEnd], false);

  return _cur_collection_initial_evac_time_ms + _cur_merge_heap_roots_time_ms;
}

double G1GCPhaseTimes::print_post_evacuate_collection_set(bool evacuation_failed) const {
  const double sum_ms = _cur_collection_nmethod_list_cleanup_time_ms +
                        _cur_ref_proc_time_ms +
                        (_weak_phase_times.total_time_sec() * MILLIUNITS) +
                        _cur_post_evacuate_cleanup_1_time_ms +
                        _cur_post_evacuate_cleanup_2_time_ms +
                        _recorded_total_rebuild_freelist_time_ms +
                        _recorded_prepare_for_mutator_time_ms +
                        _cur_expand_heap_time_ms;

  info_time("Post Evacuate Collection Set", sum_ms);

  debug_time("NMethod List Cleanup", _cur_collection_nmethod_list_cleanup_time_ms);

  debug_time_for_reference("Reference Processing", _cur_ref_proc_time_ms);
  _ref_phase_times.print_all_references(2, false);
  _weak_phase_times.log_total(2);
  _weak_phase_times.log_subtotals(3);

  debug_time("Post Evacuate Cleanup 1", _cur_post_evacuate_cleanup_1_time_ms);
  debug_phase(_gc_par_phases[MergePSS], 1);
  debug_phase(_gc_par_phases[ClearCardTable], 1);
  debug_phase(_gc_par_phases[RecalculateUsed], 1);
  if (evacuation_failed) {
    debug_phase(_gc_par_phases[RestoreEvacuationFailedRegions], 1);
    debug_phase(_gc_par_phases[RemoveSelfForwards], 2);
  }

  debug_time("Post Evacuate Cleanup 2", _cur_post_evacuate_cleanup_2_time_ms);
  if (evacuation_failed) {
    debug_phase(_gc_par_phases[RecalculateUsed], 1);
    debug_phase(_gc_par_phases[ProcessEvacuationFailedRegions], 1);
  }
#if COMPILER2_OR_JVMCI
  debug_phase(_gc_par_phases[UpdateDerivedPointers], 1);
#endif
  debug_phase(_gc_par_phases[EagerlyReclaimHumongousObjects], 1);
  trace_phase(_gc_par_phases[ResetPartialArrayStateManager]);

  if (G1CollectedHeap::heap()->should_sample_collection_set_candidates()) {
    debug_phase(_gc_par_phases[SampleCollectionSetCandidates], 1);
  }
  debug_phase(_gc_par_phases[RedirtyCards], 1);
  if (UseTLAB && ResizeTLAB) {
    debug_phase(_gc_par_phases[ResizeThreadLABs], 1);
  }
  debug_phase(_gc_par_phases[FreeCollectionSet], 1);
  trace_phase(_gc_par_phases[YoungFreeCSet], true, 1);
  trace_phase(_gc_par_phases[NonYoungFreeCSet], true, 1);

  trace_time("Serial Free Collection Set", _recorded_serial_free_cset_time_ms);

  debug_time("Rebuild Free List", _recorded_total_rebuild_freelist_time_ms);
  trace_time("Serial Rebuild Free List", _recorded_serial_rebuild_freelist_time_ms);
  trace_phase(_gc_par_phases[RebuildFreeList]);

  debug_time("Prepare For Mutator", _recorded_prepare_for_mutator_time_ms);
  debug_time("Expand Heap After Collection", _cur_expand_heap_time_ms);

  return sum_ms;
}

void G1GCPhaseTimes::print_other(double accounted_ms) const {
  info_time("Other", _gc_pause_time_ms - accounted_ms);
}

// Root-region-scan-wait, verify-before and verify-after are part of young GC,
// but these are not measured by G1Policy. i.e. these are not included in
// G1Policy::record_young_collection_start() and record_young_collection_end().
// In addition, these are not included in G1GCPhaseTimes::_gc_pause_time_ms.
// See G1YoungCollector::collect().
void G1GCPhaseTimes::print(bool evacuation_failed) {
  if (_root_region_scan_wait_time_ms > 0.0) {
    debug_time("Root Region Scan Waiting", _root_region_scan_wait_time_ms);
  }

  // Check if some time has been recorded for verification and only then print
  // the message. We do not use Verify*GC here to print because VerifyGCType
  // further limits actual verification.
  if (_cur_verify_before_time_ms > 0.0) {
    debug_time("Verify Before", _cur_verify_before_time_ms);
  }

  double accounted_ms = 0.0;

  accounted_ms += print_pre_evacuate_collection_set();
  accounted_ms += print_evacuate_initial_collection_set();
  accounted_ms += print_evacuate_optional_collection_set();
  accounted_ms += print_post_evacuate_collection_set(evacuation_failed);

  assert(_gc_pause_time_ms >= accounted_ms, "GC pause time(%.3lfms) cannot be "
         "smaller than the sum of each phase(%.3lfms).", _gc_pause_time_ms, accounted_ms);

  print_other(accounted_ms);

  // See above comment on the _cur_verify_before_time_ms check.
  if (_cur_verify_after_time_ms > 0.0) {
    debug_time("Verify After", _cur_verify_after_time_ms);
  }
}

const char* G1GCPhaseTimes::phase_name(GCParPhases phase) {
  G1GCPhaseTimes* phase_times = G1CollectedHeap::heap()->phase_times();
  return phase_times->_gc_par_phases[phase]->short_name();
}

G1EvacPhaseWithTrimTimeTracker::G1EvacPhaseWithTrimTimeTracker(G1ParScanThreadState* pss, Tickspan& total_time, Tickspan& trim_time) :
  _pss(pss),
  _start(Ticks::now()),
  _total_time(total_time),
  _trim_time(trim_time),
  _stopped(false) {

  assert(_pss->trim_ticks().value() == 0, "Possibly remaining trim ticks left over from previous use");
}

G1EvacPhaseWithTrimTimeTracker::~G1EvacPhaseWithTrimTimeTracker() {
  if (!_stopped) {
    stop();
  }
}

void G1EvacPhaseWithTrimTimeTracker::stop() {
  assert(!_stopped, "Should only be called once");
  _total_time += (Ticks::now() - _start) - _pss->trim_ticks();
  _trim_time += _pss->trim_ticks();
  _pss->reset_trim_ticks();
  _stopped = true;
}

G1GCParPhaseTimesTracker::G1GCParPhaseTimesTracker(G1GCPhaseTimes* phase_times, G1GCPhaseTimes::GCParPhases phase, uint worker_id, bool allow_multiple_record) :
  _start_time(), _phase(phase), _phase_times(phase_times), _worker_id(worker_id), _event(), _allow_multiple_record(allow_multiple_record) {
  if (_phase_times != nullptr) {
    _start_time = Ticks::now();
  }
}

G1GCParPhaseTimesTracker::~G1GCParPhaseTimesTracker() {
  if (_phase_times != nullptr) {
    if (_allow_multiple_record) {
      _phase_times->record_or_add_time_secs(_phase, _worker_id, (Ticks::now() - _start_time).seconds());
    } else {
      _phase_times->record_time_secs(_phase, _worker_id, (Ticks::now() - _start_time).seconds());
    }
    _event.commit(GCId::current(), _worker_id, G1GCPhaseTimes::phase_name(_phase));
  }
}

G1EvacPhaseTimesTracker::G1EvacPhaseTimesTracker(G1GCPhaseTimes* phase_times,
                                                 G1ParScanThreadState* pss,
                                                 G1GCPhaseTimes::GCParPhases phase,
                                                 uint worker_id) :
  G1GCParPhaseTimesTracker(phase_times, phase, worker_id),
  _total_time(),
  _trim_time(),
  _trim_tracker(pss, _total_time, _trim_time) {
}

G1EvacPhaseTimesTracker::~G1EvacPhaseTimesTracker() {
  if (_phase_times != nullptr) {
    // Explicitly stop the trim tracker since it's not yet destructed.
    _trim_tracker.stop();
    // Exclude trim time by increasing the start time.
    _start_time += _trim_time;
    _phase_times->record_or_add_time_secs(G1GCPhaseTimes::ObjCopy, _worker_id, _trim_time.seconds());
  }
}