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| 1 // Copyright (c) 2012 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 | |
| 5 #include <windows.h> | |
| 6 #include <mmsystem.h> | |
| 7 #include <process.h> | |
| 8 | |
| 9 #include <cmath> | |
| 10 #include <limits> | |
| 11 #include <vector> | |
| 12 | |
| 13 #include "base/threading/platform_thread.h" | |
| 14 #include "base/time/time.h" | |
| 15 #include "testing/gtest/include/gtest/gtest.h" | |
| 16 | |
| 17 using base::Time; | |
| 18 using base::TimeDelta; | |
| 19 using base::TimeTicks; | |
| 20 using base::TraceTicks; | |
| 21 | |
| 22 namespace { | |
| 23 | |
| 24 class MockTimeTicks : public TimeTicks { | |
| 25 public: | |
| 26 static DWORD Ticker() { | |
| 27 return static_cast<int>(InterlockedIncrement(&ticker_)); | |
| 28 } | |
| 29 | |
| 30 static void InstallTicker() { | |
| 31 old_tick_function_ = SetMockTickFunction(&Ticker); | |
| 32 ticker_ = -5; | |
| 33 } | |
| 34 | |
| 35 static void UninstallTicker() { | |
| 36 SetMockTickFunction(old_tick_function_); | |
| 37 } | |
| 38 | |
| 39 private: | |
| 40 static volatile LONG ticker_; | |
| 41 static TickFunctionType old_tick_function_; | |
| 42 }; | |
| 43 | |
| 44 volatile LONG MockTimeTicks::ticker_; | |
| 45 MockTimeTicks::TickFunctionType MockTimeTicks::old_tick_function_; | |
| 46 | |
| 47 HANDLE g_rollover_test_start; | |
| 48 | |
| 49 unsigned __stdcall RolloverTestThreadMain(void* param) { | |
| 50 int64 counter = reinterpret_cast<int64>(param); | |
| 51 DWORD rv = WaitForSingleObject(g_rollover_test_start, INFINITE); | |
| 52 EXPECT_EQ(rv, WAIT_OBJECT_0); | |
| 53 | |
| 54 TimeTicks last = TimeTicks::Now(); | |
| 55 for (int index = 0; index < counter; index++) { | |
| 56 TimeTicks now = TimeTicks::Now(); | |
| 57 int64 milliseconds = (now - last).InMilliseconds(); | |
| 58 // This is a tight loop; we could have looped faster than our | |
| 59 // measurements, so the time might be 0 millis. | |
| 60 EXPECT_GE(milliseconds, 0); | |
| 61 EXPECT_LT(milliseconds, 250); | |
| 62 last = now; | |
| 63 } | |
| 64 return 0; | |
| 65 } | |
| 66 | |
| 67 } // namespace | |
| 68 | |
| 69 TEST(TimeTicks, WinRollover) { | |
| 70 // The internal counter rolls over at ~49days. We'll use a mock | |
| 71 // timer to test this case. | |
| 72 // Basic test algorithm: | |
| 73 // 1) Set clock to rollover - N | |
| 74 // 2) Create N threads | |
| 75 // 3) Start the threads | |
| 76 // 4) Each thread loops through TimeTicks() N times | |
| 77 // 5) Each thread verifies integrity of result. | |
| 78 | |
| 79 const int kThreads = 8; | |
| 80 // Use int64 so we can cast into a void* without a compiler warning. | |
| 81 const int64 kChecks = 10; | |
| 82 | |
| 83 // It takes a lot of iterations to reproduce the bug! | |
| 84 // (See bug 1081395) | |
| 85 for (int loop = 0; loop < 4096; loop++) { | |
| 86 // Setup | |
| 87 MockTimeTicks::InstallTicker(); | |
| 88 g_rollover_test_start = CreateEvent(0, TRUE, FALSE, 0); | |
| 89 HANDLE threads[kThreads]; | |
| 90 | |
| 91 for (int index = 0; index < kThreads; index++) { | |
| 92 void* argument = reinterpret_cast<void*>(kChecks); | |
| 93 unsigned thread_id; | |
| 94 threads[index] = reinterpret_cast<HANDLE>( | |
| 95 _beginthreadex(NULL, 0, RolloverTestThreadMain, argument, 0, | |
| 96 &thread_id)); | |
| 97 EXPECT_NE((HANDLE)NULL, threads[index]); | |
| 98 } | |
| 99 | |
| 100 // Start! | |
| 101 SetEvent(g_rollover_test_start); | |
| 102 | |
| 103 // Wait for threads to finish | |
| 104 for (int index = 0; index < kThreads; index++) { | |
| 105 DWORD rv = WaitForSingleObject(threads[index], INFINITE); | |
| 106 EXPECT_EQ(rv, WAIT_OBJECT_0); | |
| 107 // Since using _beginthreadex() (as opposed to _beginthread), | |
| 108 // an explicit CloseHandle() is supposed to be called. | |
| 109 CloseHandle(threads[index]); | |
| 110 } | |
| 111 | |
| 112 CloseHandle(g_rollover_test_start); | |
| 113 | |
| 114 // Teardown | |
| 115 MockTimeTicks::UninstallTicker(); | |
| 116 } | |
| 117 } | |
| 118 | |
| 119 TEST(TimeTicks, SubMillisecondTimers) { | |
| 120 // IsHighResolution() is false on some systems. Since the product still works | |
| 121 // even if it's false, it makes this entire test questionable. | |
| 122 if (!TimeTicks::IsHighResolution()) | |
| 123 return; | |
| 124 | |
| 125 const int kRetries = 1000; | |
| 126 bool saw_submillisecond_timer = false; | |
| 127 | |
| 128 // Run kRetries attempts to see a sub-millisecond timer. | |
| 129 for (int index = 0; index < kRetries; index++) { | |
| 130 TimeTicks last_time = TimeTicks::Now(); | |
| 131 TimeDelta delta; | |
| 132 // Spin until the clock has detected a change. | |
| 133 do { | |
| 134 delta = TimeTicks::Now() - last_time; | |
| 135 } while (delta.InMicroseconds() == 0); | |
| 136 if (delta.InMicroseconds() < 1000) { | |
| 137 saw_submillisecond_timer = true; | |
| 138 break; | |
| 139 } | |
| 140 } | |
| 141 EXPECT_TRUE(saw_submillisecond_timer); | |
| 142 } | |
| 143 | |
| 144 TEST(TimeTicks, TimeGetTimeCaps) { | |
| 145 // Test some basic assumptions that we expect about how timeGetDevCaps works. | |
| 146 | |
| 147 TIMECAPS caps; | |
| 148 MMRESULT status = timeGetDevCaps(&caps, sizeof(caps)); | |
| 149 EXPECT_EQ(TIMERR_NOERROR, status); | |
| 150 if (status != TIMERR_NOERROR) { | |
| 151 printf("Could not get timeGetDevCaps\n"); | |
| 152 return; | |
| 153 } | |
| 154 | |
| 155 EXPECT_GE(static_cast<int>(caps.wPeriodMin), 1); | |
| 156 EXPECT_GT(static_cast<int>(caps.wPeriodMax), 1); | |
| 157 EXPECT_GE(static_cast<int>(caps.wPeriodMin), 1); | |
| 158 EXPECT_GT(static_cast<int>(caps.wPeriodMax), 1); | |
| 159 printf("timeGetTime range is %d to %dms\n", caps.wPeriodMin, | |
| 160 caps.wPeriodMax); | |
| 161 } | |
| 162 | |
| 163 TEST(TimeTicks, QueryPerformanceFrequency) { | |
| 164 // Test some basic assumptions that we expect about QPC. | |
| 165 | |
| 166 LARGE_INTEGER frequency; | |
| 167 BOOL rv = QueryPerformanceFrequency(&frequency); | |
| 168 EXPECT_EQ(TRUE, rv); | |
| 169 EXPECT_GT(frequency.QuadPart, 1000000); // Expect at least 1MHz | |
| 170 printf("QueryPerformanceFrequency is %5.2fMHz\n", | |
| 171 frequency.QuadPart / 1000000.0); | |
| 172 } | |
| 173 | |
| 174 TEST(TimeTicks, TimerPerformance) { | |
| 175 // Verify that various timer mechanisms can always complete quickly. | |
| 176 // Note: This is a somewhat arbitrary test. | |
| 177 const int kLoops = 10000; | |
| 178 | |
| 179 typedef TimeTicks (*TestFunc)(); | |
| 180 struct TestCase { | |
| 181 TestFunc func; | |
| 182 const char *description; | |
| 183 }; | |
| 184 // Cheating a bit here: assumes sizeof(TimeTicks) == sizeof(Time) | |
| 185 // in order to create a single test case list. | |
| 186 COMPILE_ASSERT(sizeof(TimeTicks) == sizeof(Time), | |
| 187 test_only_works_with_same_sizes); | |
| 188 TestCase cases[] = { | |
| 189 { reinterpret_cast<TestFunc>(&Time::Now), "Time::Now" }, | |
| 190 { &TimeTicks::Now, "TimeTicks::Now" }, | |
| 191 { reinterpret_cast<TestFunc>(&TraceTicks::Now), "TraceTicks::Now" }, | |
| 192 { NULL, "" } | |
| 193 }; | |
| 194 | |
| 195 int test_case = 0; | |
| 196 while (cases[test_case].func) { | |
| 197 TimeTicks start = TimeTicks::Now(); | |
| 198 for (int index = 0; index < kLoops; index++) | |
| 199 cases[test_case].func(); | |
| 200 TimeTicks stop = TimeTicks::Now(); | |
| 201 // Turning off the check for acceptible delays. Without this check, | |
| 202 // the test really doesn't do much other than measure. But the | |
| 203 // measurements are still useful for testing timers on various platforms. | |
| 204 // The reason to remove the check is because the tests run on many | |
| 205 // buildbots, some of which are VMs. These machines can run horribly | |
| 206 // slow, and there is really no value for checking against a max timer. | |
| 207 //const int kMaxTime = 35; // Maximum acceptible milliseconds for test. | |
| 208 //EXPECT_LT((stop - start).InMilliseconds(), kMaxTime); | |
| 209 printf("%s: %1.2fus per call\n", cases[test_case].description, | |
| 210 (stop - start).InMillisecondsF() * 1000 / kLoops); | |
| 211 test_case++; | |
| 212 } | |
| 213 } | |
| 214 | |
| 215 TEST(TimeTicks, FromQPCValue) { | |
| 216 if (!TimeTicks::IsHighResolution()) | |
| 217 return; | |
| 218 | |
| 219 LARGE_INTEGER frequency; | |
| 220 ASSERT_TRUE(QueryPerformanceFrequency(&frequency)); | |
| 221 const int64 ticks_per_second = frequency.QuadPart; | |
| 222 ASSERT_GT(ticks_per_second, 0); | |
| 223 | |
| 224 // Generate the tick values to convert, advancing the tick count by varying | |
| 225 // amounts. These values will ensure that both the fast and overflow-safe | |
| 226 // conversion logic in FromQPCValue() is tested, and across the entire range | |
| 227 // of possible QPC tick values. | |
| 228 std::vector<int64> test_cases; | |
| 229 test_cases.push_back(0); | |
| 230 const int kNumAdvancements = 100; | |
| 231 int64 ticks = 0; | |
| 232 int64 ticks_increment = 10; | |
| 233 for (int i = 0; i < kNumAdvancements; ++i) { | |
| 234 test_cases.push_back(ticks); | |
| 235 ticks += ticks_increment; | |
| 236 ticks_increment = ticks_increment * 6 / 5; | |
| 237 } | |
| 238 test_cases.push_back(Time::kQPCOverflowThreshold - 1); | |
| 239 test_cases.push_back(Time::kQPCOverflowThreshold); | |
| 240 test_cases.push_back(Time::kQPCOverflowThreshold + 1); | |
| 241 ticks = Time::kQPCOverflowThreshold + 10; | |
| 242 ticks_increment = 10; | |
| 243 for (int i = 0; i < kNumAdvancements; ++i) { | |
| 244 test_cases.push_back(ticks); | |
| 245 ticks += ticks_increment; | |
| 246 ticks_increment = ticks_increment * 6 / 5; | |
| 247 } | |
| 248 test_cases.push_back(std::numeric_limits<int64>::max()); | |
| 249 | |
| 250 // Test that the conversions using FromQPCValue() match those computed here | |
| 251 // using simple floating-point arithmetic. The floating-point math provides | |
| 252 // enough precision to confirm the implementation is correct to the | |
| 253 // microsecond for all |test_cases| (though it would be insufficient to | |
| 254 // confirm many "very large" tick values which are not being tested here). | |
| 255 for (int64 ticks : test_cases) { | |
| 256 const double expected_microseconds_since_origin = | |
| 257 (static_cast<double>(ticks) * Time::kMicrosecondsPerSecond) / | |
| 258 ticks_per_second; | |
| 259 const TimeTicks converted_value = TimeTicks::FromQPCValue(ticks); | |
| 260 const double converted_microseconds_since_origin = | |
| 261 static_cast<double>((converted_value - TimeTicks()).InMicroseconds()); | |
| 262 EXPECT_NEAR(expected_microseconds_since_origin, | |
| 263 converted_microseconds_since_origin, | |
| 264 1.0) | |
| 265 << "ticks=" << ticks << ", to be converted via logic path: " | |
| 266 << (ticks < Time::kQPCOverflowThreshold ? "FAST" : "SAFE"); | |
| 267 } | |
| 268 } | |
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