Remove the high res timer, which is unused.

Review URL: http://codereview.chromium.org/369006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@31149 0039d316-1c4b-4281-b951-d872f2087c98

8 files changed, 0 insertions, 410 deletions

diff --git a/chrome/browser/sync/util/highres_timer.h b/chrome/browser/sync/util/highres_timer.h
deleted file mode 100644
index 2c6513d..0000000
--- a/chrome/browser/sync/util/highres_timer.h
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// High resolution timer functions defined for each OS.
-
-#include "build/build_config.h"
-
-#if defined(OS_WIN)
-#include "chrome/browser/sync/util/highres_timer_win.h"
-#elif defined(OS_MACOSX)
-#include "chrome/browser/sync/util/highres_timer_mac.h"
-#else
-#include "chrome/browser/sync/util/highres_timer_linux.h"
-#endif
diff --git a/chrome/browser/sync/util/highres_timer_linux.cc b/chrome/browser/sync/util/highres_timer_linux.cc
deleted file mode 100644
index 77350f9..0000000
--- a/chrome/browser/sync/util/highres_timer_linux.cc
+++ /dev/null
@@ -1,29 +0,0 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// High resolution timer functions for use in Linux.
-
-#include "chrome/browser/sync/util/highres_timer.h"
-
-const uint64 MICROS_IN_MILLI = 1000L;
-const uint64 MICROS_IN_HALF_MILLI = 500L;
-const uint64 MICROS_IN_HALF_SECOND = 500000L;
-
-uint64 HighresTimer::GetElapsedMs() const {
-  uint64 end_time = GetCurrentTicks();
-
-  // Scale to ms and round to nearest ms - rounding is important because
-  // otherwise the truncation error may accumulate e.g. in sums.
-  return (uint64(end_time - start_ticks_) + MICROS_IN_HALF_MILLI) /
-             MICROS_IN_MILLI;
-}
-
-uint64 HighresTimer::GetElapsedSec() const {
-  uint64 end_time = GetCurrentTicks();
-
-  // Scale to ms and round to nearest ms - rounding is important because
-  // otherwise the truncation error may accumulate e.g. in sums.
-  return (uint64(end_time - start_ticks_) + MICROS_IN_HALF_SECOND) /
-              MICROS_IN_SECOND;
-}
diff --git a/chrome/browser/sync/util/highres_timer_linux.h b/chrome/browser/sync/util/highres_timer_linux.h
deleted file mode 100644
index 01a022d..0000000
--- a/chrome/browser/sync/util/highres_timer_linux.h
+++ /dev/null
@@ -1,79 +0,0 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// High resolution timer functions for use in Linux.
-
-#ifndef CHROME_BROWSER_SYNC_UTIL_HIGHRES_TIMER_LINUX_H_
-#define CHROME_BROWSER_SYNC_UTIL_HIGHRES_TIMER_LINUX_H_
-
-#include "base/basictypes.h"
-
-#include <sys/time.h>
-
-const uint64 MICROS_IN_SECOND = 1000000L;
-
-// A handy class for reliably measuring wall-clock time with decent resolution.
-//
-// We want to measure time with high resolution on Linux. What to do?
-//
-// RDTSC? Sure, but how do you convert it to wall clock time?
-// clock_gettime? It's not in all Linuxes.
-//
-// Let's just use gettimeofday; it's good to the microsecond.
-class HighresTimer {
- public:
-  // Captures the current start time.
-  HighresTimer();
-
-  // Captures the current tick, can be used to reset a timer for reuse.
-  void Start();
-
-  // Returns the elapsed ticks with full resolution.
-  uint64 GetElapsedTicks() const;
-
-  // Returns the elapsed time in milliseconds, rounded to the nearest
-  // millisecond.
-  uint64 GetElapsedMs() const;
-
-  // Returns the elapsed time in seconds, rounded to the nearest second.
-  uint64 GetElapsedSec() const;
-
-  uint64 start_ticks() const { return start_ticks_; }
-
-  // Returns timer frequency from cache, should be less overhead than
-  // ::QueryPerformanceFrequency.
-  static uint64 GetTimerFrequency();
-  // Returns current ticks.
-  static uint64 GetCurrentTicks();
-
- private:
-  // Captured start time.
-  uint64 start_ticks_;
-};
-
-inline HighresTimer::HighresTimer() {
-  Start();
-}
-
-inline void HighresTimer::Start() {
-  start_ticks_ = GetCurrentTicks();
-}
-
-inline uint64 HighresTimer::GetTimerFrequency() {
-  // Fixed; one "tick" is one microsecond.
-  return MICROS_IN_SECOND;
-}
-
-inline uint64 HighresTimer::GetCurrentTicks() {
-  timeval tv;
-  gettimeofday(&tv, 0);
-
-  return tv.tv_sec * MICROS_IN_SECOND + tv.tv_usec;
-}
-
-inline uint64 HighresTimer::GetElapsedTicks() const {
-  return start_ticks_ - GetCurrentTicks();
-}
-
-#endif  // CHROME_BROWSER_SYNC_UTIL_HIGHRES_TIMER_LINUX_H_
diff --git a/chrome/browser/sync/util/highres_timer_mac.cc b/chrome/browser/sync/util/highres_timer_mac.cc
deleted file mode 100644
index faad058..0000000
--- a/chrome/browser/sync/util/highres_timer_mac.cc
+++ /dev/null
@@ -1,53 +0,0 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// High resolution timer functions for use on Mac OS.
-
-#include "chrome/browser/sync/util/highres_timer.h"
-
-bool HighresTimer::perf_ratio_collected_ = false;
-mach_timebase_info_data_t HighresTimer::perf_ratio_ = {0};
-
-static const uint64 kNanosInMilli = 1000000L;
-static const uint64 kNanosInHalfMilli = 500000L;
-static const uint64 kNanosInSecond = 1000000000L;
-static const uint64 kNanosInHalfSecond = 500000000L;
-
-uint64 HighresTimer::GetElapsedMs() const {
-  uint64 end_time = GetCurrentTicks();
-
-  // Scale to ms and round to nearest ms - rounding is important
-  // because otherwise the truncation error may accumulate e.g. in sums.
-  //
-  GetTimerFrequency();
-  return ((end_time - start_ticks_) * perf_ratio_.numer +
-            kNanosInHalfMilli * perf_ratio_.denom) /
-            (kNanosInMilli * perf_ratio_.denom);
-}
-
-uint64 HighresTimer::GetElapsedSec() const {
-  uint64 end_time = GetCurrentTicks();
-
-  // Scale to ms and round to nearest ms - rounding is important
-  // because otherwise the truncation error may accumulate e.g. in sums.
-  //
-  GetTimerFrequency();
-  return ((end_time - start_ticks_) * perf_ratio_.numer +
-            kNanosInHalfSecond * perf_ratio_.denom) /
-            (kNanosInSecond * perf_ratio_.denom);
-}
-
-void HighresTimer::CollectPerfRatio() {
-  mach_timebase_info(&perf_ratio_);
-  perf_ratio_collected_ = true;
-}
-
-uint64 HighresTimer::GetTimerFrequency() {
-    if (!perf_ratio_collected_)
-        CollectPerfRatio();
-    // we're losing precision by doing the division here, but this value is only
-    // used to estimate tick time by the unit tests, so we're ok.
-    return static_cast<uint64>(
-        perf_ratio_.denom * 1000000000ULL / perf_ratio_.numer);
-}
diff --git a/chrome/browser/sync/util/highres_timer_mac.h b/chrome/browser/sync/util/highres_timer_mac.h
deleted file mode 100644
index 3a35622..0000000
--- a/chrome/browser/sync/util/highres_timer_mac.h
+++ /dev/null
@@ -1,69 +0,0 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// High resolution timer functions for use on Mac OS.
-
-#ifndef CHROME_BROWSER_SYNC_UTIL_HIGHRES_TIMER_MAC_H_
-#define CHROME_BROWSER_SYNC_UTIL_HIGHRES_TIMER_MAC_H_
-
-#include <mach/mach.h>
-#include <mach/mach_time.h>
-
-#include "base/basictypes.h"
-
-// A handy class for reliably measuring wall-clock time with decent resolution.
-class HighresTimer {
- public:
-  // Captures the current start time
-  HighresTimer();
-
-  // Captures the current tick, can be used to reset a timer for reuse.
-  void Start();
-
-  // Returns the elapsed ticks with full resolution.
-  uint64 GetElapsedTicks() const;
-
-  // Returns the elapsed time in milliseconds, rounded to the nearest
-  // millisecond.
-  uint64 GetElapsedMs() const;
-
-  // Returns the elapsed time in seconds, rounded to the nearest second.
-  uint64 GetElapsedSec() const;
-
-  uint64 start_ticks() const { return start_ticks_; }
-
-  // Returns timer frequency from cache, should be less overhead than
-  // ::QueryPerformanceFrequency.
-  static uint64 GetTimerFrequency();
-  // Returns current ticks.
-  static uint64 GetCurrentTicks();
-
- private:
-  static void CollectPerfRatio();
-
-  // Captured start time.
-  uint64 start_ticks_;
-
-  // Captured performance counter frequency.
-  static bool perf_ratio_collected_;
-  static mach_timebase_info_data_t perf_ratio_;
-};
-
-inline HighresTimer::HighresTimer() {
-  Start();
-}
-
-inline void HighresTimer::Start() {
-  start_ticks_ = GetCurrentTicks();
-}
-
-inline uint64 HighresTimer::GetCurrentTicks() {
-  return mach_absolute_time();
-}
-
-inline uint64 HighresTimer::GetElapsedTicks() const {
-  return start_ticks_ - GetCurrentTicks();
-}
-
-#endif  // CHROME_BROWSER_SYNC_UTIL_HIGHRES_TIMER_MAC_H_
diff --git a/chrome/browser/sync/util/highres_timer_unittest.cc b/chrome/browser/sync/util/highres_timer_unittest.cc
deleted file mode 100644
index 2257262..0000000
--- a/chrome/browser/sync/util/highres_timer_unittest.cc
+++ /dev/null
@@ -1,41 +0,0 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// High resolution timer unit tests.
-
-#include "base/basictypes.h"
-#include "base/platform_thread.h"
-#include "build/build_config.h"
-#include "chrome/browser/sync/util/highres_timer.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-// These unittests have proven to be flaky on buildbot. While we don't want
-// them breaking the build, we still build them to guard against bitrot.
-// On dev machines during local builds we can enable them.
-TEST(HighresTimer, DISABLED_MillisecondClock) {
-  HighresTimer timer;
-
-  // Note: this could fail if we context switch between initializing the timer
-  // and here. Very unlikely however.
-  EXPECT_TRUE(0 == timer.GetElapsedMs());
-  timer.Start();
-  uint64 half_ms = HighresTimer::GetTimerFrequency() / 2000;
-  // Busy wait for half a millisecond.
-  while (timer.start_ticks() + half_ms > HighresTimer::GetCurrentTicks()) {
-    // Nothing
-  }
-  EXPECT_TRUE(1 == timer.GetElapsedMs());
-}
-
-TEST(HighresTimer, DISABLED_SecondClock) {
-  HighresTimer timer;
-
-  EXPECT_TRUE(0 == timer.GetElapsedSec());
-  PlatformThread::Sleep(250);
-  EXPECT_TRUE(0 == timer.GetElapsedSec());
-  EXPECT_TRUE(230 <= timer.GetElapsedMs());
-  EXPECT_TRUE(270 >= timer.GetElapsedMs());
-  PlatformThread::Sleep(251);
-  EXPECT_TRUE(1 == timer.GetElapsedSec());
-}
diff --git a/chrome/browser/sync/util/highres_timer_win.cc b/chrome/browser/sync/util/highres_timer_win.cc
deleted file mode 100644
index 0d7323a..0000000
--- a/chrome/browser/sync/util/highres_timer_win.cc
+++ /dev/null
@@ -1,46 +0,0 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// High resolution timer functions for use in Windows.
-
-#include "chrome/browser/sync/util/highres_timer.h"
-
-bool HighresTimer::perf_freq_collected_ = false;
-ULONGLONG HighresTimer::perf_freq_ = 0;
-
-ULONGLONG HighresTimer::GetElapsedMs() const {
-  ULONGLONG end_time = GetCurrentTicks();
-
-  // Scale to ms and round to nearest ms - rounding is important because
-  // otherwise the truncation error may accumulate e.g. in sums.
-  //
-  // Given infinite resolution, this expression could be written as:
-  //  trunc((end - start (units:freq*sec))/freq (units:sec) *
-  //                1000 (unit:ms) + 1/2 (unit:ms))
-  ULONGLONG freq = GetTimerFrequency();
-  return ((end_time - start_ticks_) * 1000L + freq / 2) / freq;
-}
-
-ULONGLONG HighresTimer::GetElapsedSec() const {
-  ULONGLONG end_time = GetCurrentTicks();
-
-  // Round to nearest ms - rounding is important because otherwise the
-  // truncation error may accumulate e.g. in sums.
-  //
-  // Given infinite resolution, this expression could be written as:
-  //  trunc((end - start (units:freq*sec))/freq (unit:sec) + 1/2 (unit:sec))
-  ULONGLONG freq = GetTimerFrequency();
-  return ((end_time - start_ticks_) + freq / 2) / freq;
-}
-
-void HighresTimer::CollectPerfFreq() {
-  LARGE_INTEGER freq;
-
-  // Note that this is racy. It's OK, however, because even concurrent
-  // executions of this are idempotent.
-  if (::QueryPerformanceFrequency(&freq)) {
-    perf_freq_ = freq.QuadPart;
-    perf_freq_collected_ = true;
-  }
-}
diff --git a/chrome/browser/sync/util/highres_timer_win.h b/chrome/browser/sync/util/highres_timer_win.h
deleted file mode 100644
index d03a872..0000000
--- a/chrome/browser/sync/util/highres_timer_win.h
+++ /dev/null
@@ -1,78 +0,0 @@
-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-//
-// High resolution timer functions for use in Windows.
-
-#ifndef CHROME_BROWSER_SYNC_UTIL_HIGHRES_TIMER_WIN_H_
-#define CHROME_BROWSER_SYNC_UTIL_HIGHRES_TIMER_WIN_H_
-
-#include <windows.h>
-
-// A handy class for reliably measuring wall-clock time with decent resolution,
-// even on multi-processor machines and on laptops (where RDTSC potentially
-// returns different results on different processors and/or the RDTSC timer
-// clocks at different rates depending on the power state of the CPU,
-// respectively).
-class HighresTimer {
- public:
-  // Captures the current start time.
-  HighresTimer();
-
-  // Captures the current tick, can be used to reset a timer for reuse.
-  void Start();
-
-  // Returns the elapsed ticks with full resolution.
-  ULONGLONG GetElapsedTicks() const;
-
-  // Returns the elapsed time in milliseconds, rounded to the nearest
-  // millisecond.
-  ULONGLONG GetElapsedMs() const;
-
-  // Returns the elapsed time in seconds, rounded to the nearest second.
-  ULONGLONG GetElapsedSec() const;
-
-  ULONGLONG start_ticks() const { return start_ticks_; }
-
-  // Returns timer frequency from cache, should be less
-  // overhead than ::QueryPerformanceFrequency.
-  static ULONGLONG GetTimerFrequency();
-  // Returns current ticks.
-  static ULONGLONG GetCurrentTicks();
-
- private:
-  static void CollectPerfFreq();
-
-  // Captured start time.
-  ULONGLONG start_ticks_;
-
-  // Captured performance counter frequency.
-  static bool perf_freq_collected_;
-  static ULONGLONG perf_freq_;
-};
-
-inline HighresTimer::HighresTimer() {
-  Start();
-}
-
-inline void HighresTimer::Start() {
-  start_ticks_ = GetCurrentTicks();
-}
-
-inline ULONGLONG HighresTimer::GetTimerFrequency() {
-  if (!perf_freq_collected_)
-    CollectPerfFreq();
-  return perf_freq_;
-}
-
-inline ULONGLONG HighresTimer::GetCurrentTicks() {
-  LARGE_INTEGER ticks;
-  ::QueryPerformanceCounter(&ticks);
-  return ticks.QuadPart;
-}
-
-inline ULONGLONG HighresTimer::GetElapsedTicks() const {
-  return start_ticks_ - GetCurrentTicks();
-}
-
-#endif  // CHROME_BROWSER_SYNC_UTIL_HIGHRES_TIMER_WIN_H_