Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 1 | // Copyright 2013 the V8 project 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 "src/base/platform/time.h" |
| 6 | |
| 7 | #if V8_OS_POSIX |
| 8 | #include <fcntl.h> // for O_RDONLY |
| 9 | #include <sys/time.h> |
| 10 | #include <unistd.h> |
| 11 | #endif |
| 12 | #if V8_OS_MACOSX |
| 13 | #include <mach/mach_time.h> |
| 14 | #endif |
| 15 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 16 | #include <cstring> |
| 17 | #include <ostream> |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 18 | |
| 19 | #if V8_OS_WIN |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 20 | #include "src/base/atomicops.h" |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 21 | #include "src/base/lazy-instance.h" |
| 22 | #include "src/base/win32-headers.h" |
| 23 | #endif |
| 24 | #include "src/base/cpu.h" |
| 25 | #include "src/base/logging.h" |
| 26 | #include "src/base/platform/platform.h" |
| 27 | |
| 28 | namespace v8 { |
| 29 | namespace base { |
| 30 | |
| 31 | TimeDelta TimeDelta::FromDays(int days) { |
| 32 | return TimeDelta(days * Time::kMicrosecondsPerDay); |
| 33 | } |
| 34 | |
| 35 | |
| 36 | TimeDelta TimeDelta::FromHours(int hours) { |
| 37 | return TimeDelta(hours * Time::kMicrosecondsPerHour); |
| 38 | } |
| 39 | |
| 40 | |
| 41 | TimeDelta TimeDelta::FromMinutes(int minutes) { |
| 42 | return TimeDelta(minutes * Time::kMicrosecondsPerMinute); |
| 43 | } |
| 44 | |
| 45 | |
| 46 | TimeDelta TimeDelta::FromSeconds(int64_t seconds) { |
| 47 | return TimeDelta(seconds * Time::kMicrosecondsPerSecond); |
| 48 | } |
| 49 | |
| 50 | |
| 51 | TimeDelta TimeDelta::FromMilliseconds(int64_t milliseconds) { |
| 52 | return TimeDelta(milliseconds * Time::kMicrosecondsPerMillisecond); |
| 53 | } |
| 54 | |
| 55 | |
| 56 | TimeDelta TimeDelta::FromNanoseconds(int64_t nanoseconds) { |
| 57 | return TimeDelta(nanoseconds / Time::kNanosecondsPerMicrosecond); |
| 58 | } |
| 59 | |
| 60 | |
| 61 | int TimeDelta::InDays() const { |
| 62 | return static_cast<int>(delta_ / Time::kMicrosecondsPerDay); |
| 63 | } |
| 64 | |
| 65 | |
| 66 | int TimeDelta::InHours() const { |
| 67 | return static_cast<int>(delta_ / Time::kMicrosecondsPerHour); |
| 68 | } |
| 69 | |
| 70 | |
| 71 | int TimeDelta::InMinutes() const { |
| 72 | return static_cast<int>(delta_ / Time::kMicrosecondsPerMinute); |
| 73 | } |
| 74 | |
| 75 | |
| 76 | double TimeDelta::InSecondsF() const { |
| 77 | return static_cast<double>(delta_) / Time::kMicrosecondsPerSecond; |
| 78 | } |
| 79 | |
| 80 | |
| 81 | int64_t TimeDelta::InSeconds() const { |
| 82 | return delta_ / Time::kMicrosecondsPerSecond; |
| 83 | } |
| 84 | |
| 85 | |
| 86 | double TimeDelta::InMillisecondsF() const { |
| 87 | return static_cast<double>(delta_) / Time::kMicrosecondsPerMillisecond; |
| 88 | } |
| 89 | |
| 90 | |
| 91 | int64_t TimeDelta::InMilliseconds() const { |
| 92 | return delta_ / Time::kMicrosecondsPerMillisecond; |
| 93 | } |
| 94 | |
| 95 | |
| 96 | int64_t TimeDelta::InNanoseconds() const { |
| 97 | return delta_ * Time::kNanosecondsPerMicrosecond; |
| 98 | } |
| 99 | |
| 100 | |
| 101 | #if V8_OS_MACOSX |
| 102 | |
| 103 | TimeDelta TimeDelta::FromMachTimespec(struct mach_timespec ts) { |
| 104 | DCHECK_GE(ts.tv_nsec, 0); |
| 105 | DCHECK_LT(ts.tv_nsec, |
| 106 | static_cast<long>(Time::kNanosecondsPerSecond)); // NOLINT |
| 107 | return TimeDelta(ts.tv_sec * Time::kMicrosecondsPerSecond + |
| 108 | ts.tv_nsec / Time::kNanosecondsPerMicrosecond); |
| 109 | } |
| 110 | |
| 111 | |
| 112 | struct mach_timespec TimeDelta::ToMachTimespec() const { |
| 113 | struct mach_timespec ts; |
| 114 | DCHECK(delta_ >= 0); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 115 | ts.tv_sec = static_cast<unsigned>(delta_ / Time::kMicrosecondsPerSecond); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 116 | ts.tv_nsec = (delta_ % Time::kMicrosecondsPerSecond) * |
| 117 | Time::kNanosecondsPerMicrosecond; |
| 118 | return ts; |
| 119 | } |
| 120 | |
| 121 | #endif // V8_OS_MACOSX |
| 122 | |
| 123 | |
| 124 | #if V8_OS_POSIX |
| 125 | |
| 126 | TimeDelta TimeDelta::FromTimespec(struct timespec ts) { |
| 127 | DCHECK_GE(ts.tv_nsec, 0); |
| 128 | DCHECK_LT(ts.tv_nsec, |
| 129 | static_cast<long>(Time::kNanosecondsPerSecond)); // NOLINT |
| 130 | return TimeDelta(ts.tv_sec * Time::kMicrosecondsPerSecond + |
| 131 | ts.tv_nsec / Time::kNanosecondsPerMicrosecond); |
| 132 | } |
| 133 | |
| 134 | |
| 135 | struct timespec TimeDelta::ToTimespec() const { |
| 136 | struct timespec ts; |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 137 | ts.tv_sec = static_cast<time_t>(delta_ / Time::kMicrosecondsPerSecond); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 138 | ts.tv_nsec = (delta_ % Time::kMicrosecondsPerSecond) * |
| 139 | Time::kNanosecondsPerMicrosecond; |
| 140 | return ts; |
| 141 | } |
| 142 | |
| 143 | #endif // V8_OS_POSIX |
| 144 | |
| 145 | |
| 146 | #if V8_OS_WIN |
| 147 | |
| 148 | // We implement time using the high-resolution timers so that we can get |
| 149 | // timeouts which are smaller than 10-15ms. To avoid any drift, we |
| 150 | // periodically resync the internal clock to the system clock. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 151 | class Clock final { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 152 | public: |
| 153 | Clock() : initial_ticks_(GetSystemTicks()), initial_time_(GetSystemTime()) {} |
| 154 | |
| 155 | Time Now() { |
| 156 | // Time between resampling the un-granular clock for this API (1 minute). |
| 157 | const TimeDelta kMaxElapsedTime = TimeDelta::FromMinutes(1); |
| 158 | |
| 159 | LockGuard<Mutex> lock_guard(&mutex_); |
| 160 | |
| 161 | // Determine current time and ticks. |
| 162 | TimeTicks ticks = GetSystemTicks(); |
| 163 | Time time = GetSystemTime(); |
| 164 | |
| 165 | // Check if we need to synchronize with the system clock due to a backwards |
| 166 | // time change or the amount of time elapsed. |
| 167 | TimeDelta elapsed = ticks - initial_ticks_; |
| 168 | if (time < initial_time_ || elapsed > kMaxElapsedTime) { |
| 169 | initial_ticks_ = ticks; |
| 170 | initial_time_ = time; |
| 171 | return time; |
| 172 | } |
| 173 | |
| 174 | return initial_time_ + elapsed; |
| 175 | } |
| 176 | |
| 177 | Time NowFromSystemTime() { |
| 178 | LockGuard<Mutex> lock_guard(&mutex_); |
| 179 | initial_ticks_ = GetSystemTicks(); |
| 180 | initial_time_ = GetSystemTime(); |
| 181 | return initial_time_; |
| 182 | } |
| 183 | |
| 184 | private: |
| 185 | static TimeTicks GetSystemTicks() { |
| 186 | return TimeTicks::Now(); |
| 187 | } |
| 188 | |
| 189 | static Time GetSystemTime() { |
| 190 | FILETIME ft; |
| 191 | ::GetSystemTimeAsFileTime(&ft); |
| 192 | return Time::FromFiletime(ft); |
| 193 | } |
| 194 | |
| 195 | TimeTicks initial_ticks_; |
| 196 | Time initial_time_; |
| 197 | Mutex mutex_; |
| 198 | }; |
| 199 | |
| 200 | |
| 201 | static LazyStaticInstance<Clock, DefaultConstructTrait<Clock>, |
| 202 | ThreadSafeInitOnceTrait>::type clock = |
| 203 | LAZY_STATIC_INSTANCE_INITIALIZER; |
| 204 | |
| 205 | |
| 206 | Time Time::Now() { |
| 207 | return clock.Pointer()->Now(); |
| 208 | } |
| 209 | |
| 210 | |
| 211 | Time Time::NowFromSystemTime() { |
| 212 | return clock.Pointer()->NowFromSystemTime(); |
| 213 | } |
| 214 | |
| 215 | |
| 216 | // Time between windows epoch and standard epoch. |
| 217 | static const int64_t kTimeToEpochInMicroseconds = V8_INT64_C(11644473600000000); |
| 218 | |
| 219 | |
| 220 | Time Time::FromFiletime(FILETIME ft) { |
| 221 | if (ft.dwLowDateTime == 0 && ft.dwHighDateTime == 0) { |
| 222 | return Time(); |
| 223 | } |
| 224 | if (ft.dwLowDateTime == std::numeric_limits<DWORD>::max() && |
| 225 | ft.dwHighDateTime == std::numeric_limits<DWORD>::max()) { |
| 226 | return Max(); |
| 227 | } |
| 228 | int64_t us = (static_cast<uint64_t>(ft.dwLowDateTime) + |
| 229 | (static_cast<uint64_t>(ft.dwHighDateTime) << 32)) / 10; |
| 230 | return Time(us - kTimeToEpochInMicroseconds); |
| 231 | } |
| 232 | |
| 233 | |
| 234 | FILETIME Time::ToFiletime() const { |
| 235 | DCHECK(us_ >= 0); |
| 236 | FILETIME ft; |
| 237 | if (IsNull()) { |
| 238 | ft.dwLowDateTime = 0; |
| 239 | ft.dwHighDateTime = 0; |
| 240 | return ft; |
| 241 | } |
| 242 | if (IsMax()) { |
| 243 | ft.dwLowDateTime = std::numeric_limits<DWORD>::max(); |
| 244 | ft.dwHighDateTime = std::numeric_limits<DWORD>::max(); |
| 245 | return ft; |
| 246 | } |
| 247 | uint64_t us = static_cast<uint64_t>(us_ + kTimeToEpochInMicroseconds) * 10; |
| 248 | ft.dwLowDateTime = static_cast<DWORD>(us); |
| 249 | ft.dwHighDateTime = static_cast<DWORD>(us >> 32); |
| 250 | return ft; |
| 251 | } |
| 252 | |
| 253 | #elif V8_OS_POSIX |
| 254 | |
| 255 | Time Time::Now() { |
| 256 | struct timeval tv; |
| 257 | int result = gettimeofday(&tv, NULL); |
| 258 | DCHECK_EQ(0, result); |
| 259 | USE(result); |
| 260 | return FromTimeval(tv); |
| 261 | } |
| 262 | |
| 263 | |
| 264 | Time Time::NowFromSystemTime() { |
| 265 | return Now(); |
| 266 | } |
| 267 | |
| 268 | |
| 269 | Time Time::FromTimespec(struct timespec ts) { |
| 270 | DCHECK(ts.tv_nsec >= 0); |
| 271 | DCHECK(ts.tv_nsec < static_cast<long>(kNanosecondsPerSecond)); // NOLINT |
| 272 | if (ts.tv_nsec == 0 && ts.tv_sec == 0) { |
| 273 | return Time(); |
| 274 | } |
| 275 | if (ts.tv_nsec == static_cast<long>(kNanosecondsPerSecond - 1) && // NOLINT |
| 276 | ts.tv_sec == std::numeric_limits<time_t>::max()) { |
| 277 | return Max(); |
| 278 | } |
| 279 | return Time(ts.tv_sec * kMicrosecondsPerSecond + |
| 280 | ts.tv_nsec / kNanosecondsPerMicrosecond); |
| 281 | } |
| 282 | |
| 283 | |
| 284 | struct timespec Time::ToTimespec() const { |
| 285 | struct timespec ts; |
| 286 | if (IsNull()) { |
| 287 | ts.tv_sec = 0; |
| 288 | ts.tv_nsec = 0; |
| 289 | return ts; |
| 290 | } |
| 291 | if (IsMax()) { |
| 292 | ts.tv_sec = std::numeric_limits<time_t>::max(); |
| 293 | ts.tv_nsec = static_cast<long>(kNanosecondsPerSecond - 1); // NOLINT |
| 294 | return ts; |
| 295 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 296 | ts.tv_sec = static_cast<time_t>(us_ / kMicrosecondsPerSecond); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 297 | ts.tv_nsec = (us_ % kMicrosecondsPerSecond) * kNanosecondsPerMicrosecond; |
| 298 | return ts; |
| 299 | } |
| 300 | |
| 301 | |
| 302 | Time Time::FromTimeval(struct timeval tv) { |
| 303 | DCHECK(tv.tv_usec >= 0); |
| 304 | DCHECK(tv.tv_usec < static_cast<suseconds_t>(kMicrosecondsPerSecond)); |
| 305 | if (tv.tv_usec == 0 && tv.tv_sec == 0) { |
| 306 | return Time(); |
| 307 | } |
| 308 | if (tv.tv_usec == static_cast<suseconds_t>(kMicrosecondsPerSecond - 1) && |
| 309 | tv.tv_sec == std::numeric_limits<time_t>::max()) { |
| 310 | return Max(); |
| 311 | } |
| 312 | return Time(tv.tv_sec * kMicrosecondsPerSecond + tv.tv_usec); |
| 313 | } |
| 314 | |
| 315 | |
| 316 | struct timeval Time::ToTimeval() const { |
| 317 | struct timeval tv; |
| 318 | if (IsNull()) { |
| 319 | tv.tv_sec = 0; |
| 320 | tv.tv_usec = 0; |
| 321 | return tv; |
| 322 | } |
| 323 | if (IsMax()) { |
| 324 | tv.tv_sec = std::numeric_limits<time_t>::max(); |
| 325 | tv.tv_usec = static_cast<suseconds_t>(kMicrosecondsPerSecond - 1); |
| 326 | return tv; |
| 327 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 328 | tv.tv_sec = static_cast<time_t>(us_ / kMicrosecondsPerSecond); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 329 | tv.tv_usec = us_ % kMicrosecondsPerSecond; |
| 330 | return tv; |
| 331 | } |
| 332 | |
| 333 | #endif // V8_OS_WIN |
| 334 | |
| 335 | |
| 336 | Time Time::FromJsTime(double ms_since_epoch) { |
| 337 | // The epoch is a valid time, so this constructor doesn't interpret |
| 338 | // 0 as the null time. |
| 339 | if (ms_since_epoch == std::numeric_limits<double>::max()) { |
| 340 | return Max(); |
| 341 | } |
| 342 | return Time( |
| 343 | static_cast<int64_t>(ms_since_epoch * kMicrosecondsPerMillisecond)); |
| 344 | } |
| 345 | |
| 346 | |
| 347 | double Time::ToJsTime() const { |
| 348 | if (IsNull()) { |
| 349 | // Preserve 0 so the invalid result doesn't depend on the platform. |
| 350 | return 0; |
| 351 | } |
| 352 | if (IsMax()) { |
| 353 | // Preserve max without offset to prevent overflow. |
| 354 | return std::numeric_limits<double>::max(); |
| 355 | } |
| 356 | return static_cast<double>(us_) / kMicrosecondsPerMillisecond; |
| 357 | } |
| 358 | |
| 359 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 360 | std::ostream& operator<<(std::ostream& os, const Time& time) { |
| 361 | return os << time.ToJsTime(); |
| 362 | } |
| 363 | |
| 364 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 365 | #if V8_OS_WIN |
| 366 | |
| 367 | class TickClock { |
| 368 | public: |
| 369 | virtual ~TickClock() {} |
| 370 | virtual int64_t Now() = 0; |
| 371 | virtual bool IsHighResolution() = 0; |
| 372 | }; |
| 373 | |
| 374 | |
| 375 | // Overview of time counters: |
| 376 | // (1) CPU cycle counter. (Retrieved via RDTSC) |
| 377 | // The CPU counter provides the highest resolution time stamp and is the least |
| 378 | // expensive to retrieve. However, the CPU counter is unreliable and should not |
| 379 | // be used in production. Its biggest issue is that it is per processor and it |
| 380 | // is not synchronized between processors. Also, on some computers, the counters |
| 381 | // will change frequency due to thermal and power changes, and stop in some |
| 382 | // states. |
| 383 | // |
| 384 | // (2) QueryPerformanceCounter (QPC). The QPC counter provides a high- |
| 385 | // resolution (100 nanoseconds) time stamp but is comparatively more expensive |
| 386 | // to retrieve. What QueryPerformanceCounter actually does is up to the HAL. |
| 387 | // (with some help from ACPI). |
| 388 | // According to http://blogs.msdn.com/oldnewthing/archive/2005/09/02/459952.aspx |
| 389 | // in the worst case, it gets the counter from the rollover interrupt on the |
| 390 | // programmable interrupt timer. In best cases, the HAL may conclude that the |
| 391 | // RDTSC counter runs at a constant frequency, then it uses that instead. On |
| 392 | // multiprocessor machines, it will try to verify the values returned from |
| 393 | // RDTSC on each processor are consistent with each other, and apply a handful |
| 394 | // of workarounds for known buggy hardware. In other words, QPC is supposed to |
| 395 | // give consistent result on a multiprocessor computer, but it is unreliable in |
| 396 | // reality due to bugs in BIOS or HAL on some, especially old computers. |
| 397 | // With recent updates on HAL and newer BIOS, QPC is getting more reliable but |
| 398 | // it should be used with caution. |
| 399 | // |
| 400 | // (3) System time. The system time provides a low-resolution (typically 10ms |
| 401 | // to 55 milliseconds) time stamp but is comparatively less expensive to |
| 402 | // retrieve and more reliable. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 403 | class HighResolutionTickClock final : public TickClock { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 404 | public: |
| 405 | explicit HighResolutionTickClock(int64_t ticks_per_second) |
| 406 | : ticks_per_second_(ticks_per_second) { |
| 407 | DCHECK_LT(0, ticks_per_second); |
| 408 | } |
| 409 | virtual ~HighResolutionTickClock() {} |
| 410 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 411 | int64_t Now() override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 412 | LARGE_INTEGER now; |
| 413 | BOOL result = QueryPerformanceCounter(&now); |
| 414 | DCHECK(result); |
| 415 | USE(result); |
| 416 | |
| 417 | // Intentionally calculate microseconds in a round about manner to avoid |
| 418 | // overflow and precision issues. Think twice before simplifying! |
| 419 | int64_t whole_seconds = now.QuadPart / ticks_per_second_; |
| 420 | int64_t leftover_ticks = now.QuadPart % ticks_per_second_; |
| 421 | int64_t ticks = (whole_seconds * Time::kMicrosecondsPerSecond) + |
| 422 | ((leftover_ticks * Time::kMicrosecondsPerSecond) / ticks_per_second_); |
| 423 | |
| 424 | // Make sure we never return 0 here, so that TimeTicks::HighResolutionNow() |
| 425 | // will never return 0. |
| 426 | return ticks + 1; |
| 427 | } |
| 428 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 429 | bool IsHighResolution() override { return true; } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 430 | |
| 431 | private: |
| 432 | int64_t ticks_per_second_; |
| 433 | }; |
| 434 | |
| 435 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 436 | class RolloverProtectedTickClock final : public TickClock { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 437 | public: |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 438 | RolloverProtectedTickClock() : rollover_(0) {} |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 439 | virtual ~RolloverProtectedTickClock() {} |
| 440 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 441 | int64_t Now() override { |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 442 | // We use timeGetTime() to implement TimeTicks::Now(), which rolls over |
| 443 | // every ~49.7 days. We try to track rollover ourselves, which works if |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 444 | // TimeTicks::Now() is called at least every 24 days. |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 445 | // Note that we do not use GetTickCount() here, since timeGetTime() gives |
| 446 | // more predictable delta values, as described here: |
| 447 | // http://blogs.msdn.com/b/larryosterman/archive/2009/09/02/what-s-the-difference-between-gettickcount-and-timegettime.aspx |
| 448 | // timeGetTime() provides 1ms granularity when combined with |
| 449 | // timeBeginPeriod(). If the host application for V8 wants fast timers, it |
| 450 | // can use timeBeginPeriod() to increase the resolution. |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 451 | // We use a lock-free version because the sampler thread calls it |
| 452 | // while having the rest of the world stopped, that could cause a deadlock. |
| 453 | base::Atomic32 rollover = base::Acquire_Load(&rollover_); |
| 454 | uint32_t now = static_cast<uint32_t>(timeGetTime()); |
| 455 | if ((now >> 31) != static_cast<uint32_t>(rollover & 1)) { |
| 456 | base::Release_CompareAndSwap(&rollover_, rollover, rollover + 1); |
| 457 | ++rollover; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 458 | } |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 459 | uint64_t ms = (static_cast<uint64_t>(rollover) << 31) | now; |
| 460 | return static_cast<int64_t>(ms * Time::kMicrosecondsPerMillisecond); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 461 | } |
| 462 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 463 | bool IsHighResolution() override { return false; } |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 464 | |
| 465 | private: |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 466 | base::Atomic32 rollover_; |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 467 | }; |
| 468 | |
| 469 | |
| 470 | static LazyStaticInstance<RolloverProtectedTickClock, |
| 471 | DefaultConstructTrait<RolloverProtectedTickClock>, |
| 472 | ThreadSafeInitOnceTrait>::type tick_clock = |
| 473 | LAZY_STATIC_INSTANCE_INITIALIZER; |
| 474 | |
| 475 | |
| 476 | struct CreateHighResTickClockTrait { |
| 477 | static TickClock* Create() { |
| 478 | // Check if the installed hardware supports a high-resolution performance |
| 479 | // counter, and if not fallback to the low-resolution tick clock. |
| 480 | LARGE_INTEGER ticks_per_second; |
| 481 | if (!QueryPerformanceFrequency(&ticks_per_second)) { |
| 482 | return tick_clock.Pointer(); |
| 483 | } |
| 484 | |
| 485 | // On Athlon X2 CPUs (e.g. model 15) the QueryPerformanceCounter |
| 486 | // is unreliable, fallback to the low-resolution tick clock. |
| 487 | CPU cpu; |
| 488 | if (strcmp(cpu.vendor(), "AuthenticAMD") == 0 && cpu.family() == 15) { |
| 489 | return tick_clock.Pointer(); |
| 490 | } |
| 491 | |
| 492 | return new HighResolutionTickClock(ticks_per_second.QuadPart); |
| 493 | } |
| 494 | }; |
| 495 | |
| 496 | |
| 497 | static LazyDynamicInstance<TickClock, CreateHighResTickClockTrait, |
| 498 | ThreadSafeInitOnceTrait>::type high_res_tick_clock = |
| 499 | LAZY_DYNAMIC_INSTANCE_INITIALIZER; |
| 500 | |
| 501 | |
| 502 | TimeTicks TimeTicks::Now() { |
| 503 | // Make sure we never return 0 here. |
| 504 | TimeTicks ticks(tick_clock.Pointer()->Now()); |
| 505 | DCHECK(!ticks.IsNull()); |
| 506 | return ticks; |
| 507 | } |
| 508 | |
| 509 | |
| 510 | TimeTicks TimeTicks::HighResolutionNow() { |
| 511 | // Make sure we never return 0 here. |
| 512 | TimeTicks ticks(high_res_tick_clock.Pointer()->Now()); |
| 513 | DCHECK(!ticks.IsNull()); |
| 514 | return ticks; |
| 515 | } |
| 516 | |
| 517 | |
| 518 | // static |
| 519 | bool TimeTicks::IsHighResolutionClockWorking() { |
| 520 | return high_res_tick_clock.Pointer()->IsHighResolution(); |
| 521 | } |
| 522 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 523 | #else // V8_OS_WIN |
| 524 | |
| 525 | TimeTicks TimeTicks::Now() { |
| 526 | return HighResolutionNow(); |
| 527 | } |
| 528 | |
| 529 | |
| 530 | TimeTicks TimeTicks::HighResolutionNow() { |
| 531 | int64_t ticks; |
| 532 | #if V8_OS_MACOSX |
| 533 | static struct mach_timebase_info info; |
| 534 | if (info.denom == 0) { |
| 535 | kern_return_t result = mach_timebase_info(&info); |
| 536 | DCHECK_EQ(KERN_SUCCESS, result); |
| 537 | USE(result); |
| 538 | } |
| 539 | ticks = (mach_absolute_time() / Time::kNanosecondsPerMicrosecond * |
| 540 | info.numer / info.denom); |
| 541 | #elif V8_OS_SOLARIS |
| 542 | ticks = (gethrtime() / Time::kNanosecondsPerMicrosecond); |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 543 | #elif V8_OS_POSIX |
| 544 | struct timespec ts; |
| 545 | int result = clock_gettime(CLOCK_MONOTONIC, &ts); |
| 546 | DCHECK_EQ(0, result); |
| 547 | USE(result); |
| 548 | ticks = (ts.tv_sec * Time::kMicrosecondsPerSecond + |
| 549 | ts.tv_nsec / Time::kNanosecondsPerMicrosecond); |
| 550 | #endif // V8_OS_MACOSX |
| 551 | // Make sure we never return 0 here. |
| 552 | return TimeTicks(ticks + 1); |
| 553 | } |
| 554 | |
| 555 | |
| 556 | // static |
| 557 | bool TimeTicks::IsHighResolutionClockWorking() { |
| 558 | return true; |
| 559 | } |
| 560 | |
Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 561 | #endif // V8_OS_WIN |
| 562 | |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 563 | } // namespace base |
| 564 | } // namespace v8 |