summaryrefslogtreecommitdiff
path: root/deps/v8/src/base/platform/time.cc
diff options
context:
space:
mode:
Diffstat (limited to 'deps/v8/src/base/platform/time.cc')
-rw-r--r--deps/v8/src/base/platform/time.cc654
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