observer_list_perftest.cc 4.3 KB

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  1. // Copyright 2018 The Chromium Authors. All rights reserved.
  2. // Use of this source code is governed by a BSD-style license that can be
  3. // found in the LICENSE file.
  4. #include "base/observer_list.h"
  5. #include <memory>
  6. #include "base/check_op.h"
  7. #include "base/strings/stringprintf.h"
  8. #include "base/time/time.h"
  9. #include "testing/gtest/include/gtest/gtest.h"
  10. #include "testing/perf/perf_result_reporter.h"
  11. // Ask the compiler not to use a register for this counter, in case it decides
  12. // to do magic optimizations like |counter += kLaps|.
  13. volatile int g_observer_list_perf_test_counter;
  14. namespace base {
  15. constexpr char kMetricPrefixObserverList[] = "ObserverList.";
  16. constexpr char kMetricNotifyTimePerObserver[] = "notify_time_per_observer";
  17. namespace {
  18. perf_test::PerfResultReporter SetUpReporter(const std::string& story_name) {
  19. perf_test::PerfResultReporter reporter(kMetricPrefixObserverList, story_name);
  20. reporter.RegisterImportantMetric(kMetricNotifyTimePerObserver, "ns");
  21. return reporter;
  22. }
  23. } // namespace
  24. class ObserverInterface {
  25. public:
  26. ObserverInterface() = default;
  27. ObserverInterface(const ObserverInterface&) = delete;
  28. ObserverInterface& operator=(const ObserverInterface&) = delete;
  29. virtual ~ObserverInterface() = default;
  30. virtual void Observe() const {
  31. g_observer_list_perf_test_counter = g_observer_list_perf_test_counter + 1;
  32. }
  33. };
  34. class UnsafeObserver : public ObserverInterface {};
  35. class TestCheckedObserver : public CheckedObserver, public ObserverInterface {};
  36. template <class ObserverType>
  37. struct Pick {
  38. // The ObserverList type to use. Checked observers need to be in a checked
  39. // ObserverList.
  40. using ObserverListType = ObserverList<ObserverType>;
  41. static const char* GetName() { return "CheckedObserver"; }
  42. };
  43. template <>
  44. struct Pick<UnsafeObserver> {
  45. using ObserverListType = ObserverList<ObserverInterface>::Unchecked;
  46. static const char* GetName() { return "UnsafeObserver"; }
  47. };
  48. template <class ObserverType>
  49. class ObserverListPerfTest : public ::testing::Test {
  50. public:
  51. using ObserverListType = typename Pick<ObserverType>::ObserverListType;
  52. ObserverListPerfTest() = default;
  53. ObserverListPerfTest(const ObserverListPerfTest&) = delete;
  54. ObserverListPerfTest& operator=(const ObserverListPerfTest&) = delete;
  55. };
  56. typedef ::testing::Types<UnsafeObserver, TestCheckedObserver> ObserverTypes;
  57. TYPED_TEST_SUITE(ObserverListPerfTest, ObserverTypes);
  58. // Performance test for base::ObserverList and Checked Observers.
  59. TYPED_TEST(ObserverListPerfTest, NotifyPerformance) {
  60. constexpr int kMaxObservers = 128;
  61. #if DCHECK_IS_ON()
  62. // The test takes about 100x longer in debug builds, mostly due to sequence
  63. // checker overheads when WeakPtr gets involved.
  64. constexpr int kLaps = 1000000;
  65. #else
  66. constexpr int kLaps = 100000000;
  67. #endif
  68. constexpr int kWarmupLaps = 100;
  69. std::vector<std::unique_ptr<TypeParam>> observers;
  70. for (int observer_count = 0; observer_count <= kMaxObservers;
  71. observer_count = observer_count ? observer_count * 2 : 1) {
  72. typename TestFixture::ObserverListType list;
  73. for (int i = 0; i < observer_count; ++i)
  74. observers.push_back(std::make_unique<TypeParam>());
  75. for (auto& o : observers)
  76. list.AddObserver(o.get());
  77. for (int i = 0; i < kWarmupLaps; ++i) {
  78. for (auto& o : list)
  79. o.Observe();
  80. }
  81. g_observer_list_perf_test_counter = 0;
  82. const int weighted_laps = kLaps / (observer_count + 1);
  83. TimeTicks start = TimeTicks::Now();
  84. for (int i = 0; i < weighted_laps; ++i) {
  85. for (auto& o : list)
  86. o.Observe();
  87. }
  88. TimeDelta duration = TimeTicks::Now() - start;
  89. observers.clear();
  90. EXPECT_EQ(observer_count * weighted_laps,
  91. g_observer_list_perf_test_counter);
  92. EXPECT_TRUE(observer_count == 0 || !list.empty());
  93. std::string story_name =
  94. base::StringPrintf("%s_%d", Pick<TypeParam>::GetName(), observer_count);
  95. // A typical value is 3-20 nanoseconds per observe in Release, 1000-2000ns
  96. // in an optimized build with DCHECKs and 3000-6000ns in debug builds.
  97. auto reporter = SetUpReporter(story_name);
  98. reporter.AddResult(
  99. kMetricNotifyTimePerObserver,
  100. duration.InNanoseconds() /
  101. static_cast<double>(g_observer_list_perf_test_counter +
  102. weighted_laps));
  103. }
  104. }
  105. } // namespace base