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| 1 /* | |
| 2 * Copyright 2014 The WebRTC Project Authors. All rights reserved. | |
| 3 * | |
| 4 * Use of this source code is governed by a BSD-style license | |
| 5 * that can be found in the LICENSE file in the root of the source | |
| 6 * tree. An additional intellectual property rights grant can be found | |
| 7 * in the file PATENTS. All contributing project authors may | |
| 8 * be found in the AUTHORS file in the root of the source tree. | |
| 9 */ | |
| 10 | |
| 11 #include <memory> | |
| 12 #include <set> | |
| 13 #include <vector> | |
| 14 | |
| 15 #include "webrtc/base/arraysize.h" | |
| 16 #include "webrtc/base/checks.h" | |
| 17 #include "webrtc/base/criticalsection.h" | |
| 18 #include "webrtc/base/event.h" | |
| 19 #include "webrtc/base/gunit.h" | |
| 20 #include "webrtc/base/platform_thread.h" | |
| 21 #include "webrtc/base/thread.h" | |
| 22 | |
| 23 namespace rtc { | |
| 24 | |
| 25 namespace { | |
| 26 | |
| 27 const int kLongTime = 10000; // 10 seconds | |
| 28 const int kNumThreads = 16; | |
| 29 const int kOperationsToRun = 1000; | |
| 30 | |
| 31 class UniqueValueVerifier { | |
| 32 public: | |
| 33 void Verify(const std::vector<int>& values) { | |
| 34 for (size_t i = 0; i < values.size(); ++i) { | |
| 35 std::pair<std::set<int>::iterator, bool> result = | |
| 36 all_values_.insert(values[i]); | |
| 37 // Each value should only be taken by one thread, so if this value | |
| 38 // has already been added, something went wrong. | |
| 39 EXPECT_TRUE(result.second) | |
| 40 << " Thread=" << Thread::Current() << " value=" << values[i]; | |
| 41 } | |
| 42 } | |
| 43 | |
| 44 void Finalize() {} | |
| 45 | |
| 46 private: | |
| 47 std::set<int> all_values_; | |
| 48 }; | |
| 49 | |
| 50 class CompareAndSwapVerifier { | |
| 51 public: | |
| 52 CompareAndSwapVerifier() : zero_count_(0) {} | |
| 53 | |
| 54 void Verify(const std::vector<int>& values) { | |
| 55 for (auto v : values) { | |
| 56 if (v == 0) { | |
| 57 EXPECT_EQ(0, zero_count_) << "Thread=" << Thread::Current(); | |
| 58 ++zero_count_; | |
| 59 } else { | |
| 60 EXPECT_EQ(1, v) << " Thread=" << Thread::Current(); | |
| 61 } | |
| 62 } | |
| 63 } | |
| 64 | |
| 65 void Finalize() { | |
| 66 EXPECT_EQ(1, zero_count_); | |
| 67 } | |
| 68 private: | |
| 69 int zero_count_; | |
| 70 }; | |
| 71 | |
| 72 class RunnerBase : public MessageHandler { | |
| 73 public: | |
| 74 explicit RunnerBase(int value) | |
| 75 : threads_active_(0), | |
| 76 start_event_(true, false), | |
| 77 done_event_(true, false), | |
| 78 shared_value_(value) {} | |
| 79 | |
| 80 bool Run() { | |
| 81 // Signal all threads to start. | |
| 82 start_event_.Set(); | |
| 83 | |
| 84 // Wait for all threads to finish. | |
| 85 return done_event_.Wait(kLongTime); | |
| 86 } | |
| 87 | |
| 88 void SetExpectedThreadCount(int count) { | |
| 89 threads_active_ = count; | |
| 90 } | |
| 91 | |
| 92 int shared_value() const { return shared_value_; } | |
| 93 | |
| 94 protected: | |
| 95 // Derived classes must override OnMessage, and call BeforeStart and AfterEnd | |
| 96 // at the beginning and the end of OnMessage respectively. | |
| 97 void BeforeStart() { | |
| 98 ASSERT_TRUE(start_event_.Wait(kLongTime)); | |
| 99 } | |
| 100 | |
| 101 // Returns true if all threads have finished. | |
| 102 bool AfterEnd() { | |
| 103 if (AtomicOps::Decrement(&threads_active_) == 0) { | |
| 104 done_event_.Set(); | |
| 105 return true; | |
| 106 } | |
| 107 return false; | |
| 108 } | |
| 109 | |
| 110 int threads_active_; | |
| 111 Event start_event_; | |
| 112 Event done_event_; | |
| 113 int shared_value_; | |
| 114 }; | |
| 115 | |
| 116 class LOCKABLE CriticalSectionLock { | |
| 117 public: | |
| 118 void Lock() EXCLUSIVE_LOCK_FUNCTION() { | |
| 119 cs_.Enter(); | |
| 120 } | |
| 121 void Unlock() UNLOCK_FUNCTION() { | |
| 122 cs_.Leave(); | |
| 123 } | |
| 124 | |
| 125 private: | |
| 126 CriticalSection cs_; | |
| 127 }; | |
| 128 | |
| 129 template <class Lock> | |
| 130 class LockRunner : public RunnerBase { | |
| 131 public: | |
| 132 LockRunner() : RunnerBase(0) {} | |
| 133 | |
| 134 void OnMessage(Message* msg) override { | |
| 135 BeforeStart(); | |
| 136 | |
| 137 lock_.Lock(); | |
| 138 | |
| 139 EXPECT_EQ(0, shared_value_); | |
| 140 int old = shared_value_; | |
| 141 | |
| 142 // Use a loop to increase the chance of race. | |
| 143 for (int i = 0; i < kOperationsToRun; ++i) { | |
| 144 ++shared_value_; | |
| 145 } | |
| 146 EXPECT_EQ(old + kOperationsToRun, shared_value_); | |
| 147 shared_value_ = 0; | |
| 148 | |
| 149 lock_.Unlock(); | |
| 150 | |
| 151 AfterEnd(); | |
| 152 } | |
| 153 | |
| 154 private: | |
| 155 Lock lock_; | |
| 156 }; | |
| 157 | |
| 158 template <class Op, class Verifier> | |
| 159 class AtomicOpRunner : public RunnerBase { | |
| 160 public: | |
| 161 explicit AtomicOpRunner(int initial_value) : RunnerBase(initial_value) {} | |
| 162 | |
| 163 void OnMessage(Message* msg) override { | |
| 164 BeforeStart(); | |
| 165 | |
| 166 std::vector<int> values; | |
| 167 values.reserve(kOperationsToRun); | |
| 168 | |
| 169 // Generate a bunch of values by updating shared_value_ atomically. | |
| 170 for (int i = 0; i < kOperationsToRun; ++i) { | |
| 171 values.push_back(Op::AtomicOp(&shared_value_)); | |
| 172 } | |
| 173 | |
| 174 { // Add them all to the set. | |
| 175 CritScope cs(&all_values_crit_); | |
| 176 verifier_.Verify(values); | |
| 177 } | |
| 178 | |
| 179 if (AfterEnd()) { | |
| 180 verifier_.Finalize(); | |
| 181 } | |
| 182 } | |
| 183 | |
| 184 private: | |
| 185 CriticalSection all_values_crit_; | |
| 186 Verifier verifier_; | |
| 187 }; | |
| 188 | |
| 189 struct IncrementOp { | |
| 190 static int AtomicOp(int* i) { return AtomicOps::Increment(i); } | |
| 191 }; | |
| 192 | |
| 193 struct DecrementOp { | |
| 194 static int AtomicOp(int* i) { return AtomicOps::Decrement(i); } | |
| 195 }; | |
| 196 | |
| 197 struct CompareAndSwapOp { | |
| 198 static int AtomicOp(int* i) { return AtomicOps::CompareAndSwap(i, 0, 1); } | |
| 199 }; | |
| 200 | |
| 201 void StartThreads(std::vector<std::unique_ptr<Thread>>* threads, | |
| 202 MessageHandler* handler) { | |
| 203 for (int i = 0; i < kNumThreads; ++i) { | |
| 204 std::unique_ptr<Thread> thread(new Thread()); | |
| 205 thread->Start(); | |
| 206 thread->Post(RTC_FROM_HERE, handler); | |
| 207 threads->push_back(std::move(thread)); | |
| 208 } | |
| 209 } | |
| 210 | |
| 211 } // namespace | |
| 212 | |
| 213 TEST(AtomicOpsTest, Simple) { | |
| 214 int value = 0; | |
| 215 EXPECT_EQ(1, AtomicOps::Increment(&value)); | |
| 216 EXPECT_EQ(1, value); | |
| 217 EXPECT_EQ(2, AtomicOps::Increment(&value)); | |
| 218 EXPECT_EQ(2, value); | |
| 219 EXPECT_EQ(1, AtomicOps::Decrement(&value)); | |
| 220 EXPECT_EQ(1, value); | |
| 221 EXPECT_EQ(0, AtomicOps::Decrement(&value)); | |
| 222 EXPECT_EQ(0, value); | |
| 223 } | |
| 224 | |
| 225 TEST(AtomicOpsTest, SimplePtr) { | |
| 226 class Foo {}; | |
| 227 Foo* volatile foo = nullptr; | |
| 228 std::unique_ptr<Foo> a(new Foo()); | |
| 229 std::unique_ptr<Foo> b(new Foo()); | |
| 230 // Reading the initial value should work as expected. | |
| 231 EXPECT_TRUE(rtc::AtomicOps::AcquireLoadPtr(&foo) == nullptr); | |
| 232 // Setting using compare and swap should work. | |
| 233 EXPECT_TRUE(rtc::AtomicOps::CompareAndSwapPtr( | |
| 234 &foo, static_cast<Foo*>(nullptr), a.get()) == nullptr); | |
| 235 EXPECT_TRUE(rtc::AtomicOps::AcquireLoadPtr(&foo) == a.get()); | |
| 236 // Setting another value but with the wrong previous pointer should fail | |
| 237 // (remain a). | |
| 238 EXPECT_TRUE(rtc::AtomicOps::CompareAndSwapPtr( | |
| 239 &foo, static_cast<Foo*>(nullptr), b.get()) == a.get()); | |
| 240 EXPECT_TRUE(rtc::AtomicOps::AcquireLoadPtr(&foo) == a.get()); | |
| 241 // Replacing a with b should work. | |
| 242 EXPECT_TRUE(rtc::AtomicOps::CompareAndSwapPtr(&foo, a.get(), b.get()) == | |
| 243 a.get()); | |
| 244 EXPECT_TRUE(rtc::AtomicOps::AcquireLoadPtr(&foo) == b.get()); | |
| 245 } | |
| 246 | |
| 247 TEST(AtomicOpsTest, Increment) { | |
| 248 // Create and start lots of threads. | |
| 249 AtomicOpRunner<IncrementOp, UniqueValueVerifier> runner(0); | |
| 250 std::vector<std::unique_ptr<Thread>> threads; | |
| 251 StartThreads(&threads, &runner); | |
| 252 runner.SetExpectedThreadCount(kNumThreads); | |
| 253 | |
| 254 // Release the hounds! | |
| 255 EXPECT_TRUE(runner.Run()); | |
| 256 EXPECT_EQ(kOperationsToRun * kNumThreads, runner.shared_value()); | |
| 257 } | |
| 258 | |
| 259 TEST(AtomicOpsTest, Decrement) { | |
| 260 // Create and start lots of threads. | |
| 261 AtomicOpRunner<DecrementOp, UniqueValueVerifier> runner( | |
| 262 kOperationsToRun * kNumThreads); | |
| 263 std::vector<std::unique_ptr<Thread>> threads; | |
| 264 StartThreads(&threads, &runner); | |
| 265 runner.SetExpectedThreadCount(kNumThreads); | |
| 266 | |
| 267 // Release the hounds! | |
| 268 EXPECT_TRUE(runner.Run()); | |
| 269 EXPECT_EQ(0, runner.shared_value()); | |
| 270 } | |
| 271 | |
| 272 TEST(AtomicOpsTest, CompareAndSwap) { | |
| 273 // Create and start lots of threads. | |
| 274 AtomicOpRunner<CompareAndSwapOp, CompareAndSwapVerifier> runner(0); | |
| 275 std::vector<std::unique_ptr<Thread>> threads; | |
| 276 StartThreads(&threads, &runner); | |
| 277 runner.SetExpectedThreadCount(kNumThreads); | |
| 278 | |
| 279 // Release the hounds! | |
| 280 EXPECT_TRUE(runner.Run()); | |
| 281 EXPECT_EQ(1, runner.shared_value()); | |
| 282 } | |
| 283 | |
| 284 TEST(GlobalLockTest, Basic) { | |
| 285 // Create and start lots of threads. | |
| 286 LockRunner<GlobalLock> runner; | |
| 287 std::vector<std::unique_ptr<Thread>> threads; | |
| 288 StartThreads(&threads, &runner); | |
| 289 runner.SetExpectedThreadCount(kNumThreads); | |
| 290 | |
| 291 // Release the hounds! | |
| 292 EXPECT_TRUE(runner.Run()); | |
| 293 EXPECT_EQ(0, runner.shared_value()); | |
| 294 } | |
| 295 | |
| 296 TEST(CriticalSectionTest, Basic) { | |
| 297 // Create and start lots of threads. | |
| 298 LockRunner<CriticalSectionLock> runner; | |
| 299 std::vector<std::unique_ptr<Thread>> threads; | |
| 300 StartThreads(&threads, &runner); | |
| 301 runner.SetExpectedThreadCount(kNumThreads); | |
| 302 | |
| 303 // Release the hounds! | |
| 304 EXPECT_TRUE(runner.Run()); | |
| 305 EXPECT_EQ(0, runner.shared_value()); | |
| 306 } | |
| 307 | |
| 308 class PerfTestData { | |
| 309 public: | |
| 310 PerfTestData(int expected_count, Event* event) | |
| 311 : cache_line_barrier_1_(), cache_line_barrier_2_(), | |
| 312 expected_count_(expected_count), event_(event) { | |
| 313 cache_line_barrier_1_[0]++; // Avoid 'is not used'. | |
| 314 cache_line_barrier_2_[0]++; // Avoid 'is not used'. | |
| 315 } | |
| 316 ~PerfTestData() {} | |
| 317 | |
| 318 void AddToCounter(int add) { | |
| 319 rtc::CritScope cs(&lock_); | |
| 320 my_counter_ += add; | |
| 321 if (my_counter_ == expected_count_) | |
| 322 event_->Set(); | |
| 323 } | |
| 324 | |
| 325 int64_t total() const { | |
| 326 // Assume that only one thread is running now. | |
| 327 return my_counter_; | |
| 328 } | |
| 329 | |
| 330 private: | |
| 331 uint8_t cache_line_barrier_1_[64]; | |
| 332 CriticalSection lock_; | |
| 333 uint8_t cache_line_barrier_2_[64]; | |
| 334 int64_t my_counter_ = 0; | |
| 335 const int expected_count_; | |
| 336 Event* const event_; | |
| 337 }; | |
| 338 | |
| 339 class PerfTestThread { | |
| 340 public: | |
| 341 PerfTestThread() : thread_(&ThreadFunc, this, "CsPerf") {} | |
| 342 | |
| 343 void Start(PerfTestData* data, int repeats, int id) { | |
| 344 RTC_DCHECK(!thread_.IsRunning()); | |
| 345 RTC_DCHECK(!data_); | |
| 346 data_ = data; | |
| 347 repeats_ = repeats; | |
| 348 my_id_ = id; | |
| 349 thread_.Start(); | |
| 350 } | |
| 351 | |
| 352 void Stop() { | |
| 353 RTC_DCHECK(thread_.IsRunning()); | |
| 354 RTC_DCHECK(data_); | |
| 355 thread_.Stop(); | |
| 356 repeats_ = 0; | |
| 357 data_ = nullptr; | |
| 358 my_id_ = 0; | |
| 359 } | |
| 360 | |
| 361 private: | |
| 362 static bool ThreadFunc(void* param) { | |
| 363 PerfTestThread* me = static_cast<PerfTestThread*>(param); | |
| 364 for (int i = 0; i < me->repeats_; ++i) | |
| 365 me->data_->AddToCounter(me->my_id_); | |
| 366 return false; | |
| 367 } | |
| 368 | |
| 369 PlatformThread thread_; | |
| 370 PerfTestData* data_ = nullptr; | |
| 371 int repeats_ = 0; | |
| 372 int my_id_ = 0; | |
| 373 }; | |
| 374 | |
| 375 // Comparison of output of this test as tested on a MacBook Pro Retina, 15-inch, | |
| 376 // Mid 2014, 2,8 GHz Intel Core i7, 16 GB 1600 MHz DDR3, | |
| 377 // running OS X El Capitan, 10.11.2. | |
| 378 // | |
| 379 // Native mutex implementation: | |
| 380 // Approximate CPU usage: | |
| 381 // System: ~16% | |
| 382 // User mode: ~1.3% | |
| 383 // Idle: ~82% | |
| 384 // Unit test output: | |
| 385 // [ OK ] CriticalSectionTest.Performance (234545 ms) | |
| 386 // | |
| 387 // Special partially spin lock based implementation: | |
| 388 // Approximate CPU usage: | |
| 389 // System: ~75% | |
| 390 // User mode: ~16% | |
| 391 // Idle: ~8% | |
| 392 // Unit test output: | |
| 393 // [ OK ] CriticalSectionTest.Performance (2107 ms) | |
| 394 // | |
| 395 // The test is disabled by default to avoid unecessarily loading the bots. | |
| 396 TEST(CriticalSectionTest, DISABLED_Performance) { | |
| 397 PerfTestThread threads[8]; | |
| 398 Event event(false, false); | |
| 399 | |
| 400 static const int kThreadRepeats = 10000000; | |
| 401 static const int kExpectedCount = kThreadRepeats * arraysize(threads); | |
| 402 PerfTestData test_data(kExpectedCount, &event); | |
| 403 | |
| 404 for (auto& t : threads) | |
| 405 t.Start(&test_data, kThreadRepeats, 1); | |
| 406 | |
| 407 event.Wait(Event::kForever); | |
| 408 | |
| 409 for (auto& t : threads) | |
| 410 t.Stop(); | |
| 411 } | |
| 412 | |
| 413 } // namespace rtc | |
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