Revert "Add Chromium-style TimeDelta, Time and TimeTicks classes, and a new ElapsedTimer class."

src/time/time.cc

-// Copyright 2013 the V8 project authors. All rights reserved.
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-//       notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-//       copyright notice, this list of conditions and the following
-//       disclaimer in the documentation and/or other materials provided
-//       with the distribution.
-//     * Neither the name of Google Inc. nor the names of its
-//       contributors may be used to endorse or promote products derived
-//       from this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-#include "time.h"
-
-#if V8_OS_POSIX
-#include <sys/time.h>
-#endif
-#if V8_OS_MACOSX
-#include <mach/mach_time.h>
-#endif
-
-#include <cstring>
-
-#include "checks.h"
-#include "cpu.h"
-#include "platform.h"
-#if V8_OS_WIN
-#define V8_WIN32_HEADERS_FULL
-#include "win32-headers.h"
-#endif
-
-namespace v8 {
-namespace internal {
-
-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_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_time_(CurrentWallclockTime()),
-            initial_ticks_(TimeTicks::Now()),
-            mutex_(OS::CreateMutex()) {}
-
-  ~Clock() { delete mutex_; }
-
-  Time Now() {
-    // This must be executed under lock.
-    ScopedLock sl(mutex_);
-
-    // Calculate the time elapsed since we started our timer.
-    TimeDelta elapsed = TimeTicks::Now() - initial_ticks_;
-
-    // Check if we don't need to synchronize with the wallclock yet.
-    if (elapsed.InMicroseconds() <= kMaxMicrosecondsToAvoidDrift) {
-      return initial_time_ + elapsed;
-    }
-
-    // Resynchronize with the wallclock.
-    initial_ticks_ = TimeTicks::Now();
-    initial_time_ = CurrentWallclockTime();
-    return initial_time_;
-  }
-
-  Time NowFromSystemTime() {
-    ScopedLock sl(mutex_);
-    initial_ticks_ = TimeTicks::Now();
-    initial_time_ = CurrentWallclockTime();
-    return initial_time_;
-  }
-
- private:
-  // Time between resampling the un-granular clock for this API (1 minute).
-  static const int64_t kMaxMicrosecondsToAvoidDrift =
-      Time::kMicrosecondsPerMinute;
-
-  static Time CurrentWallclockTime() {
-    FILETIME ft;
-    ::GetSystemTimeAsFileTime(&ft);
-    return Time::FromFiletime(ft);
-  }
-
-  TimeTicks initial_ticks_;
-  Time initial_time_;
-  Mutex* mutex_;
-};
-
-
-static LazyDynamicInstance<Clock,
-    DefaultCreateTrait<Clock>,
-    ThreadSafeInitOnceTrait>::type clock = LAZY_DYNAMIC_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 {
-  ASSERT(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);
-  ASSERT_EQ(0, result);
-  USE(result);
-  return FromTimeval(tv);
-}
-
-
-Time Time::NowFromSystemTime() {
-  return Now();
-}
-
-
-Time Time::FromTimeval(struct timeval tv) {
-  ASSERT(tv.tv_usec >= 0);
-  ASSERT(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;
-};
-
-
-// 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) {
-    ASSERT_NE(0, ticks_per_second);
-  }
-  virtual ~HighResolutionTickClock() {}
-
-  virtual int64_t Now() V8_OVERRIDE {
-    LARGE_INTEGER now;
-    BOOL result = QueryPerformanceCounter(&now);
-    ASSERT(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::HighResNow()
-    // will never return 0.
-    return ticks + 1;
-  }
-
- private:
-  int64_t ticks_per_second_;
-};
-
-
-class RolloverProtectedTickClock V8_FINAL : public TickClock {
- public:
-  RolloverProtectedTickClock()
-      : mutex_(OS::CreateMutex()), last_seen_now_(0), rollover_ms_(1) {
-    // We initialize rollover_ms_ to 1 to ensure that we will never
-    // return 0 from TimeTicks::HighResNow() and TimeTicks::Now() below.
-  }
-  virtual ~RolloverProtectedTickClock() { delete mutex_; }
-
-  virtual int64_t Now() V8_OVERRIDE {
-    ScopedLock sl(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
-    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_;
-  }
-
- private:
-  Mutex* mutex_;
-  DWORD last_seen_now_;
-  int64_t rollover_ms_;
-};
-
-
-static LazyDynamicInstance<RolloverProtectedTickClock,
-    DefaultCreateTrait<RolloverProtectedTickClock>,
-    ThreadSafeInitOnceTrait>::type tick_clock =
-        LAZY_DYNAMIC_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());
-  ASSERT(!ticks.IsNull());
-  return ticks;
-}
-
-
-TimeTicks TimeTicks::HighResNow() {
-  // Make sure we never return 0 here.
-  TimeTicks ticks(high_res_tick_clock.Pointer()->Now());
-  ASSERT(!ticks.IsNull());
-  return ticks;
-}
-
-#else  // V8_OS_WIN
-
-TimeTicks TimeTicks::Now() {
-  return HighResNow();
-}
-
-
-TimeTicks TimeTicks::HighResNow() {
-  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);
-    ASSERT_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_OS_POSIX
-  struct timespec ts;
-  int result = clock_gettime(CLOCK_MONOTONIC, &ts);
-  ASSERT_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);
-}
-
-#endif  // V8_OS_WIN
-
-} }  // namespace v8::internal