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Diffstat (limited to 'deps/v8/src/base/platform/time.cc')
-rw-r--r-- | deps/v8/src/base/platform/time.cc | 654 |
1 files changed, 654 insertions, 0 deletions
diff --git a/deps/v8/src/base/platform/time.cc b/deps/v8/src/base/platform/time.cc new file mode 100644 index 000000000..4d1bec2b2 --- /dev/null +++ b/deps/v8/src/base/platform/time.cc @@ -0,0 +1,654 @@ +// Copyright 2013 the V8 project authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +#include "src/base/platform/time.h" + +#if V8_OS_POSIX +#include <fcntl.h> // for O_RDONLY +#include <sys/time.h> +#include <unistd.h> +#endif +#if V8_OS_MACOSX +#include <mach/mach_time.h> +#endif + +#include <string.h> + +#if V8_OS_WIN +#include "src/base/lazy-instance.h" +#include "src/base/win32-headers.h" +#endif +#include "src/base/cpu.h" +#include "src/base/logging.h" +#include "src/base/platform/platform.h" + +namespace v8 { +namespace base { + +TimeDelta TimeDelta::FromDays(int days) { + return TimeDelta(days * Time::kMicrosecondsPerDay); +} + + +TimeDelta TimeDelta::FromHours(int hours) { + return TimeDelta(hours * Time::kMicrosecondsPerHour); +} + + +TimeDelta TimeDelta::FromMinutes(int minutes) { + return TimeDelta(minutes * Time::kMicrosecondsPerMinute); +} + + +TimeDelta TimeDelta::FromSeconds(int64_t seconds) { + return TimeDelta(seconds * Time::kMicrosecondsPerSecond); +} + + +TimeDelta TimeDelta::FromMilliseconds(int64_t milliseconds) { + return TimeDelta(milliseconds * Time::kMicrosecondsPerMillisecond); +} + + +TimeDelta TimeDelta::FromNanoseconds(int64_t nanoseconds) { + return TimeDelta(nanoseconds / Time::kNanosecondsPerMicrosecond); +} + + +int TimeDelta::InDays() const { + return static_cast<int>(delta_ / Time::kMicrosecondsPerDay); +} + + +int TimeDelta::InHours() const { + return static_cast<int>(delta_ / Time::kMicrosecondsPerHour); +} + + +int TimeDelta::InMinutes() const { + return static_cast<int>(delta_ / Time::kMicrosecondsPerMinute); +} + + +double TimeDelta::InSecondsF() const { + return static_cast<double>(delta_) / Time::kMicrosecondsPerSecond; +} + + +int64_t TimeDelta::InSeconds() const { + return delta_ / Time::kMicrosecondsPerSecond; +} + + +double TimeDelta::InMillisecondsF() const { + return static_cast<double>(delta_) / Time::kMicrosecondsPerMillisecond; +} + + +int64_t TimeDelta::InMilliseconds() const { + return delta_ / Time::kMicrosecondsPerMillisecond; +} + + +int64_t TimeDelta::InNanoseconds() const { + return delta_ * Time::kNanosecondsPerMicrosecond; +} + + +#if V8_OS_MACOSX + +TimeDelta TimeDelta::FromMachTimespec(struct mach_timespec ts) { + DCHECK_GE(ts.tv_nsec, 0); + DCHECK_LT(ts.tv_nsec, + static_cast<long>(Time::kNanosecondsPerSecond)); // NOLINT + return TimeDelta(ts.tv_sec * Time::kMicrosecondsPerSecond + + ts.tv_nsec / Time::kNanosecondsPerMicrosecond); +} + + +struct mach_timespec TimeDelta::ToMachTimespec() const { + struct mach_timespec ts; + DCHECK(delta_ >= 0); + ts.tv_sec = delta_ / Time::kMicrosecondsPerSecond; + ts.tv_nsec = (delta_ % Time::kMicrosecondsPerSecond) * + Time::kNanosecondsPerMicrosecond; + return ts; +} + +#endif // V8_OS_MACOSX + + +#if V8_OS_POSIX + +TimeDelta TimeDelta::FromTimespec(struct timespec ts) { + DCHECK_GE(ts.tv_nsec, 0); + DCHECK_LT(ts.tv_nsec, + static_cast<long>(Time::kNanosecondsPerSecond)); // NOLINT + return TimeDelta(ts.tv_sec * Time::kMicrosecondsPerSecond + + ts.tv_nsec / Time::kNanosecondsPerMicrosecond); +} + + +struct timespec TimeDelta::ToTimespec() const { + struct timespec ts; + ts.tv_sec = delta_ / Time::kMicrosecondsPerSecond; + ts.tv_nsec = (delta_ % Time::kMicrosecondsPerSecond) * + Time::kNanosecondsPerMicrosecond; + return ts; +} + +#endif // V8_OS_POSIX + + +#if V8_OS_WIN + +// We implement time using the high-resolution timers so that we can get +// timeouts which are smaller than 10-15ms. To avoid any drift, we +// periodically resync the internal clock to the system clock. +class Clock V8_FINAL { + public: + Clock() : initial_ticks_(GetSystemTicks()), initial_time_(GetSystemTime()) {} + + Time Now() { + // Time between resampling the un-granular clock for this API (1 minute). + const TimeDelta kMaxElapsedTime = TimeDelta::FromMinutes(1); + + LockGuard<Mutex> lock_guard(&mutex_); + + // Determine current time and ticks. + TimeTicks ticks = GetSystemTicks(); + Time time = GetSystemTime(); + + // Check if we need to synchronize with the system clock due to a backwards + // time change or the amount of time elapsed. + TimeDelta elapsed = ticks - initial_ticks_; + if (time < initial_time_ || elapsed > kMaxElapsedTime) { + initial_ticks_ = ticks; + initial_time_ = time; + return time; + } + + return initial_time_ + elapsed; + } + + Time NowFromSystemTime() { + LockGuard<Mutex> lock_guard(&mutex_); + initial_ticks_ = GetSystemTicks(); + initial_time_ = GetSystemTime(); + return initial_time_; + } + + private: + static TimeTicks GetSystemTicks() { + return TimeTicks::Now(); + } + + static Time GetSystemTime() { + FILETIME ft; + ::GetSystemTimeAsFileTime(&ft); + return Time::FromFiletime(ft); + } + + TimeTicks initial_ticks_; + Time initial_time_; + Mutex mutex_; +}; + + +static LazyStaticInstance<Clock, DefaultConstructTrait<Clock>, + ThreadSafeInitOnceTrait>::type clock = + LAZY_STATIC_INSTANCE_INITIALIZER; + + +Time Time::Now() { + return clock.Pointer()->Now(); +} + + +Time Time::NowFromSystemTime() { + return clock.Pointer()->NowFromSystemTime(); +} + + +// Time between windows epoch and standard epoch. +static const int64_t kTimeToEpochInMicroseconds = V8_INT64_C(11644473600000000); + + +Time Time::FromFiletime(FILETIME ft) { + if (ft.dwLowDateTime == 0 && ft.dwHighDateTime == 0) { + return Time(); + } + if (ft.dwLowDateTime == std::numeric_limits<DWORD>::max() && + ft.dwHighDateTime == std::numeric_limits<DWORD>::max()) { + return Max(); + } + int64_t us = (static_cast<uint64_t>(ft.dwLowDateTime) + + (static_cast<uint64_t>(ft.dwHighDateTime) << 32)) / 10; + return Time(us - kTimeToEpochInMicroseconds); +} + + +FILETIME Time::ToFiletime() const { + DCHECK(us_ >= 0); + FILETIME ft; + if (IsNull()) { + ft.dwLowDateTime = 0; + ft.dwHighDateTime = 0; + return ft; + } + if (IsMax()) { + ft.dwLowDateTime = std::numeric_limits<DWORD>::max(); + ft.dwHighDateTime = std::numeric_limits<DWORD>::max(); + return ft; + } + uint64_t us = static_cast<uint64_t>(us_ + kTimeToEpochInMicroseconds) * 10; + ft.dwLowDateTime = static_cast<DWORD>(us); + ft.dwHighDateTime = static_cast<DWORD>(us >> 32); + return ft; +} + +#elif V8_OS_POSIX + +Time Time::Now() { + struct timeval tv; + int result = gettimeofday(&tv, NULL); + DCHECK_EQ(0, result); + USE(result); + return FromTimeval(tv); +} + + +Time Time::NowFromSystemTime() { + return Now(); +} + + +Time Time::FromTimespec(struct timespec ts) { + DCHECK(ts.tv_nsec >= 0); + DCHECK(ts.tv_nsec < static_cast<long>(kNanosecondsPerSecond)); // NOLINT + if (ts.tv_nsec == 0 && ts.tv_sec == 0) { + return Time(); + } + if (ts.tv_nsec == static_cast<long>(kNanosecondsPerSecond - 1) && // NOLINT + ts.tv_sec == std::numeric_limits<time_t>::max()) { + return Max(); + } + return Time(ts.tv_sec * kMicrosecondsPerSecond + + ts.tv_nsec / kNanosecondsPerMicrosecond); +} + + +struct timespec Time::ToTimespec() const { + struct timespec ts; + if (IsNull()) { + ts.tv_sec = 0; + ts.tv_nsec = 0; + return ts; + } + if (IsMax()) { + ts.tv_sec = std::numeric_limits<time_t>::max(); + ts.tv_nsec = static_cast<long>(kNanosecondsPerSecond - 1); // NOLINT + return ts; + } + ts.tv_sec = us_ / kMicrosecondsPerSecond; + ts.tv_nsec = (us_ % kMicrosecondsPerSecond) * kNanosecondsPerMicrosecond; + return ts; +} + + +Time Time::FromTimeval(struct timeval tv) { + DCHECK(tv.tv_usec >= 0); + DCHECK(tv.tv_usec < static_cast<suseconds_t>(kMicrosecondsPerSecond)); + if (tv.tv_usec == 0 && tv.tv_sec == 0) { + return Time(); + } + if (tv.tv_usec == static_cast<suseconds_t>(kMicrosecondsPerSecond - 1) && + tv.tv_sec == std::numeric_limits<time_t>::max()) { + return Max(); + } + return Time(tv.tv_sec * kMicrosecondsPerSecond + tv.tv_usec); +} + + +struct timeval Time::ToTimeval() const { + struct timeval tv; + if (IsNull()) { + tv.tv_sec = 0; + tv.tv_usec = 0; + return tv; + } + if (IsMax()) { + tv.tv_sec = std::numeric_limits<time_t>::max(); + tv.tv_usec = static_cast<suseconds_t>(kMicrosecondsPerSecond - 1); + return tv; + } + tv.tv_sec = us_ / kMicrosecondsPerSecond; + tv.tv_usec = us_ % kMicrosecondsPerSecond; + return tv; +} + +#endif // V8_OS_WIN + + +Time Time::FromJsTime(double ms_since_epoch) { + // The epoch is a valid time, so this constructor doesn't interpret + // 0 as the null time. + if (ms_since_epoch == std::numeric_limits<double>::max()) { + return Max(); + } + return Time( + static_cast<int64_t>(ms_since_epoch * kMicrosecondsPerMillisecond)); +} + + +double Time::ToJsTime() const { + if (IsNull()) { + // Preserve 0 so the invalid result doesn't depend on the platform. + return 0; + } + if (IsMax()) { + // Preserve max without offset to prevent overflow. + return std::numeric_limits<double>::max(); + } + return static_cast<double>(us_) / kMicrosecondsPerMillisecond; +} + + +#if V8_OS_WIN + +class TickClock { + public: + virtual ~TickClock() {} + virtual int64_t Now() = 0; + virtual bool IsHighResolution() = 0; +}; + + +// Overview of time counters: +// (1) CPU cycle counter. (Retrieved via RDTSC) +// The CPU counter provides the highest resolution time stamp and is the least +// expensive to retrieve. However, the CPU counter is unreliable and should not +// be used in production. Its biggest issue is that it is per processor and it +// is not synchronized between processors. Also, on some computers, the counters +// will change frequency due to thermal and power changes, and stop in some +// states. +// +// (2) QueryPerformanceCounter (QPC). The QPC counter provides a high- +// resolution (100 nanoseconds) time stamp but is comparatively more expensive +// to retrieve. What QueryPerformanceCounter actually does is up to the HAL. +// (with some help from ACPI). +// According to http://blogs.msdn.com/oldnewthing/archive/2005/09/02/459952.aspx +// in the worst case, it gets the counter from the rollover interrupt on the +// programmable interrupt timer. In best cases, the HAL may conclude that the +// RDTSC counter runs at a constant frequency, then it uses that instead. On +// multiprocessor machines, it will try to verify the values returned from +// RDTSC on each processor are consistent with each other, and apply a handful +// of workarounds for known buggy hardware. In other words, QPC is supposed to +// give consistent result on a multiprocessor computer, but it is unreliable in +// reality due to bugs in BIOS or HAL on some, especially old computers. +// With recent updates on HAL and newer BIOS, QPC is getting more reliable but +// it should be used with caution. +// +// (3) System time. The system time provides a low-resolution (typically 10ms +// to 55 milliseconds) time stamp but is comparatively less expensive to +// retrieve and more reliable. +class HighResolutionTickClock V8_FINAL : public TickClock { + public: + explicit HighResolutionTickClock(int64_t ticks_per_second) + : ticks_per_second_(ticks_per_second) { + DCHECK_LT(0, ticks_per_second); + } + virtual ~HighResolutionTickClock() {} + + virtual int64_t Now() V8_OVERRIDE { + LARGE_INTEGER now; + BOOL result = QueryPerformanceCounter(&now); + DCHECK(result); + USE(result); + + // Intentionally calculate microseconds in a round about manner to avoid + // overflow and precision issues. Think twice before simplifying! + int64_t whole_seconds = now.QuadPart / ticks_per_second_; + int64_t leftover_ticks = now.QuadPart % ticks_per_second_; + int64_t ticks = (whole_seconds * Time::kMicrosecondsPerSecond) + + ((leftover_ticks * Time::kMicrosecondsPerSecond) / ticks_per_second_); + + // Make sure we never return 0 here, so that TimeTicks::HighResolutionNow() + // will never return 0. + return ticks + 1; + } + + virtual bool IsHighResolution() V8_OVERRIDE { + return true; + } + + private: + int64_t ticks_per_second_; +}; + + +class RolloverProtectedTickClock V8_FINAL : public TickClock { + public: + // We initialize rollover_ms_ to 1 to ensure that we will never + // return 0 from TimeTicks::HighResolutionNow() and TimeTicks::Now() below. + RolloverProtectedTickClock() : last_seen_now_(0), rollover_ms_(1) {} + virtual ~RolloverProtectedTickClock() {} + + virtual int64_t Now() V8_OVERRIDE { + LockGuard<Mutex> lock_guard(&mutex_); + // We use timeGetTime() to implement TimeTicks::Now(), which rolls over + // every ~49.7 days. We try to track rollover ourselves, which works if + // TimeTicks::Now() is called at least every 49 days. + // Note that we do not use GetTickCount() here, since timeGetTime() gives + // more predictable delta values, as described here: + // http://blogs.msdn.com/b/larryosterman/archive/2009/09/02/what-s-the-difference-between-gettickcount-and-timegettime.aspx + // timeGetTime() provides 1ms granularity when combined with + // timeBeginPeriod(). If the host application for V8 wants fast timers, it + // can use timeBeginPeriod() to increase the resolution. + DWORD now = timeGetTime(); + if (now < last_seen_now_) { + rollover_ms_ += V8_INT64_C(0x100000000); // ~49.7 days. + } + last_seen_now_ = now; + return (now + rollover_ms_) * Time::kMicrosecondsPerMillisecond; + } + + virtual bool IsHighResolution() V8_OVERRIDE { + return false; + } + + private: + Mutex mutex_; + DWORD last_seen_now_; + int64_t rollover_ms_; +}; + + +static LazyStaticInstance<RolloverProtectedTickClock, + DefaultConstructTrait<RolloverProtectedTickClock>, + ThreadSafeInitOnceTrait>::type tick_clock = + LAZY_STATIC_INSTANCE_INITIALIZER; + + +struct CreateHighResTickClockTrait { + static TickClock* Create() { + // Check if the installed hardware supports a high-resolution performance + // counter, and if not fallback to the low-resolution tick clock. + LARGE_INTEGER ticks_per_second; + if (!QueryPerformanceFrequency(&ticks_per_second)) { + return tick_clock.Pointer(); + } + + // On Athlon X2 CPUs (e.g. model 15) the QueryPerformanceCounter + // is unreliable, fallback to the low-resolution tick clock. + CPU cpu; + if (strcmp(cpu.vendor(), "AuthenticAMD") == 0 && cpu.family() == 15) { + return tick_clock.Pointer(); + } + + return new HighResolutionTickClock(ticks_per_second.QuadPart); + } +}; + + +static LazyDynamicInstance<TickClock, CreateHighResTickClockTrait, + ThreadSafeInitOnceTrait>::type high_res_tick_clock = + LAZY_DYNAMIC_INSTANCE_INITIALIZER; + + +TimeTicks TimeTicks::Now() { + // Make sure we never return 0 here. + TimeTicks ticks(tick_clock.Pointer()->Now()); + DCHECK(!ticks.IsNull()); + return ticks; +} + + +TimeTicks TimeTicks::HighResolutionNow() { + // Make sure we never return 0 here. + TimeTicks ticks(high_res_tick_clock.Pointer()->Now()); + DCHECK(!ticks.IsNull()); + return ticks; +} + + +// static +bool TimeTicks::IsHighResolutionClockWorking() { + return high_res_tick_clock.Pointer()->IsHighResolution(); +} + + +// static +TimeTicks TimeTicks::KernelTimestampNow() { return TimeTicks(0); } + + +// static +bool TimeTicks::KernelTimestampAvailable() { return false; } + +#else // V8_OS_WIN + +TimeTicks TimeTicks::Now() { + return HighResolutionNow(); +} + + +TimeTicks TimeTicks::HighResolutionNow() { + int64_t ticks; +#if V8_OS_MACOSX + static struct mach_timebase_info info; + if (info.denom == 0) { + kern_return_t result = mach_timebase_info(&info); + DCHECK_EQ(KERN_SUCCESS, result); + USE(result); + } + ticks = (mach_absolute_time() / Time::kNanosecondsPerMicrosecond * + info.numer / info.denom); +#elif V8_OS_SOLARIS + ticks = (gethrtime() / Time::kNanosecondsPerMicrosecond); +#elif V8_LIBRT_NOT_AVAILABLE + // TODO(bmeurer): This is a temporary hack to support cross-compiling + // Chrome for Android in AOSP. Remove this once AOSP is fixed, also + // cleanup the tools/gyp/v8.gyp file. + struct timeval tv; + int result = gettimeofday(&tv, NULL); + DCHECK_EQ(0, result); + USE(result); + ticks = (tv.tv_sec * Time::kMicrosecondsPerSecond + tv.tv_usec); +#elif V8_OS_POSIX + struct timespec ts; + int result = clock_gettime(CLOCK_MONOTONIC, &ts); + DCHECK_EQ(0, result); + USE(result); + ticks = (ts.tv_sec * Time::kMicrosecondsPerSecond + + ts.tv_nsec / Time::kNanosecondsPerMicrosecond); +#endif // V8_OS_MACOSX + // Make sure we never return 0 here. + return TimeTicks(ticks + 1); +} + + +// static +bool TimeTicks::IsHighResolutionClockWorking() { + return true; +} + + +#if V8_OS_LINUX && !V8_LIBRT_NOT_AVAILABLE + +class KernelTimestampClock { + public: + KernelTimestampClock() : clock_fd_(-1), clock_id_(kClockInvalid) { + clock_fd_ = open(kTraceClockDevice, O_RDONLY); + if (clock_fd_ == -1) { + return; + } + clock_id_ = get_clockid(clock_fd_); + } + + virtual ~KernelTimestampClock() { + if (clock_fd_ != -1) { + close(clock_fd_); + } + } + + int64_t Now() { + if (clock_id_ == kClockInvalid) { + return 0; + } + + struct timespec ts; + + clock_gettime(clock_id_, &ts); + return ((int64_t)ts.tv_sec * kNsecPerSec) + ts.tv_nsec; + } + + bool Available() { return clock_id_ != kClockInvalid; } + + private: + static const clockid_t kClockInvalid = -1; + static const char kTraceClockDevice[]; + static const uint64_t kNsecPerSec = 1000000000; + + int clock_fd_; + clockid_t clock_id_; + + static int get_clockid(int fd) { return ((~(clockid_t)(fd) << 3) | 3); } +}; + + +// Timestamp module name +const char KernelTimestampClock::kTraceClockDevice[] = "/dev/trace_clock"; + +#else + +class KernelTimestampClock { + public: + KernelTimestampClock() {} + + int64_t Now() { return 0; } + bool Available() { return false; } +}; + +#endif // V8_OS_LINUX && !V8_LIBRT_NOT_AVAILABLE + +static LazyStaticInstance<KernelTimestampClock, + DefaultConstructTrait<KernelTimestampClock>, + ThreadSafeInitOnceTrait>::type kernel_tick_clock = + LAZY_STATIC_INSTANCE_INITIALIZER; + + +// static +TimeTicks TimeTicks::KernelTimestampNow() { + return TimeTicks(kernel_tick_clock.Pointer()->Now()); +} + + +// static +bool TimeTicks::KernelTimestampAvailable() { + return kernel_tick_clock.Pointer()->Available(); +} + +#endif // V8_OS_WIN + +} } // namespace v8::base |