garbage_collector.h revision e76e70f424468f311c2061c291e8384263f3968c 
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ART_RUNTIME_GC_COLLECTOR_GARBAGE_COLLECTOR_H_
18#define ART_RUNTIME_GC_COLLECTOR_GARBAGE_COLLECTOR_H_
19
20#include "base/histogram.h"
21#include "base/mutex.h"
22#include "base/timing_logger.h"
23#include "gc/collector_type.h"
24#include "gc/gc_cause.h"
25#include "gc_type.h"
26#include <stdint.h>
27#include <vector>
28
29namespace art {
30namespace gc {
31
32class Heap;
33
34namespace collector {
35
36class GarbageCollector {
37 public:
38  class SCOPED_LOCKABLE ScopedPause {
39   public:
40    explicit ScopedPause(GarbageCollector* collector) EXCLUSIVE_LOCK_FUNCTION(Locks::mutator_lock_);
41    ~ScopedPause() UNLOCK_FUNCTION();
42
43   private:
44    const uint64_t start_time_;
45    GarbageCollector* const collector_;
46  };
47
48  GarbageCollector(Heap* heap, const std::string& name);
49  virtual ~GarbageCollector() { }
50
51  const char* GetName() const {
52    return name_.c_str();
53  }
54
55  virtual GcType GetGcType() const = 0;
56
57  virtual CollectorType GetCollectorType() const = 0;
58
59  // Run the garbage collector.
60  void Run(GcCause gc_cause, bool clear_soft_references);
61
62  Heap* GetHeap() const {
63    return heap_;
64  }
65
66  // Returns how long the mutators were paused in nanoseconds.
67  const std::vector<uint64_t>& GetPauseTimes() const {
68    return pause_times_;
69  }
70
71  // Returns how long the GC took to complete in nanoseconds.
72  uint64_t GetDurationNs() const {
73    return duration_ns_;
74  }
75
76  void RegisterPause(uint64_t nano_length);
77
78  TimingLogger& GetTimings() {
79    return timings_;
80  }
81  const CumulativeLogger& GetCumulativeTimings() const {
82    return cumulative_timings_;
83  }
84
85  void ResetCumulativeStatistics();
86
87  // Swap the live and mark bitmaps of spaces that are active for the collector. For partial GC,
88  // this is the allocation space, for full GC then we swap the zygote bitmaps too.
89  void SwapBitmaps() EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_);
90
91  int64_t GetFreedBytes() const {
92    return freed_bytes_;
93  }
94
95  int64_t GetFreedLargeObjectBytes() const {
96    return freed_large_object_bytes_;
97  }
98
99  uint64_t GetFreedObjects() const {
100    return freed_objects_;
101  }
102
103  uint64_t GetFreedLargeObjects() const {
104    return freed_large_objects_;
105  }
106
107  uint64_t GetTotalPausedTimeNs() const {
108    return pause_histogram_.Sum();
109  }
110
111  int64_t GetTotalFreedBytes() const {
112    return total_freed_bytes_;
113  }
114
115  uint64_t GetTotalFreedObjects() const {
116    return total_freed_objects_;
117  }
118
119  const Histogram<uint64_t>& GetPauseHistogram() const {
120    return pause_histogram_;
121  }
122
123  // Reset the cumulative timings and pause histogram.
124  void ResetMeasurements();
125
126  // Returns the estimated throughput in bytes / second.
127  uint64_t GetEstimatedMeanThroughput() const;
128
129  // Returns the estimated throughput of the last GC iteration.
130  uint64_t GetEstimatedLastIterationThroughput() const;
131
132  // Returns how many GC iterations have been run.
133  size_t GetIterations() const {
134    return GetCumulativeTimings().GetIterations();
135  }
136
137 protected:
138  // Run all of the GC phases.
139  virtual void RunPhases() = 0;
140
141  // Revoke all the thread-local buffers.
142  virtual void RevokeAllThreadLocalBuffers() = 0;
143
144  // Record that you have freed some objects or large objects, calls Heap::RecordFree.
145  // TODO: These are not thread safe, add a lock if we get have parallel sweeping.
146  void RecordFree(uint64_t freed_objects, int64_t freed_bytes);
147  void RecordFreeLargeObjects(uint64_t freed_objects, int64_t freed_bytes);
148
149  static constexpr size_t kPauseBucketSize = 500;
150  static constexpr size_t kPauseBucketCount = 32;
151
152  Heap* const heap_;
153
154  std::string name_;
155
156  GcCause gc_cause_;
157  bool clear_soft_references_;
158
159  uint64_t duration_ns_;
160  TimingLogger timings_;
161
162  // Cumulative statistics.
163  Histogram<uint64_t> pause_histogram_;
164  uint64_t total_time_ns_;
165  uint64_t total_freed_objects_;
166  int64_t total_freed_bytes_;
167
168  // Single GC statitstics, freed bytes are signed since the GC can free negative bytes if it
169  // promotes objects to a space which has a larger allocation size.
170  int64_t freed_bytes_;
171  int64_t freed_large_object_bytes_;
172  uint64_t freed_objects_;
173  uint64_t freed_large_objects_;
174
175  CumulativeLogger cumulative_timings_;
176
177  std::vector<uint64_t> pause_times_;
178};
179
180}  // namespace collector
181}  // namespace gc
182}  // namespace art
183
184#endif  // ART_RUNTIME_GC_COLLECTOR_GARBAGE_COLLECTOR_H_
185