| Index: chrome/browser/metrics/time_ticks_experiment_win.cc
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| diff --git a/chrome/browser/metrics/time_ticks_experiment_win.cc b/chrome/browser/metrics/time_ticks_experiment_win.cc
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| deleted file mode 100644
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| index 3f81ba1fb985594bbb633cd58a0e75f35a5115d8..0000000000000000000000000000000000000000
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| --- a/chrome/browser/metrics/time_ticks_experiment_win.cc
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| +++ /dev/null
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| @@ -1,116 +0,0 @@
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| -// Copyright (c) 2013 The Chromium Authors. All rights reserved.
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| -// Use of this source code is governed by a BSD-style license that can be
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| -// found in the LICENSE file.
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| -
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| -#include "chrome/browser/metrics/time_ticks_experiment_win.h"
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| -
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| -#if defined(OS_WIN)
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| -
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| -#include <windows.h>
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| -#include <algorithm>
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| -
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| -#include "base/cpu.h"
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| -#include "base/metrics/histogram_macros.h"
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| -#include "base/win/windows_version.h"
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| -#include "build/build_config.h"
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| -
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| -namespace chrome {
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| -
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| -namespace {
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| -
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| -const int kNumIterations = 1000;
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| -
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| -}  // anonymous namespace
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| -
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| -void CollectTimeTicksStats() {
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| -  // This bit is supposed to indicate that rdtsc is safe across cores. If so, we
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| -  // can use QPC as long as it uses rdtsc.
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| -  // TODO(simonjam): We should look for other signals that QPC might be safe and
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| -  // test them out here.
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| -  base::CPU cpu;
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| -  UMA_HISTOGRAM_BOOLEAN("WinTimeTicks.NonStopTsc",
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| -                        cpu.has_non_stop_time_stamp_counter());
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| -  if (!cpu.has_non_stop_time_stamp_counter()) {
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| -    return;
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| -  }
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| -
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| -  DWORD_PTR default_mask;
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| -  DWORD_PTR system_mask;
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| -  if (!GetProcessAffinityMask(GetCurrentProcess(),
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| -                              &default_mask, &system_mask)) {
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| -    return;
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| -  }
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| -  if (!default_mask) {
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| -    return;
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| -  }
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| -
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| -  DWORD_PTR current_mask = 1;
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| -  bool failed_to_change_cores = false;
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| -
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| -  base::win::OSInfo* info = base::win::OSInfo::GetInstance();
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| -  UMA_HISTOGRAM_ENUMERATION("WinTimeTicks.VersionTotal", info->version(),
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| -                            base::win::VERSION_WIN_LAST);
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| -
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| -  LARGE_INTEGER qpc_frequency;
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| -  QueryPerformanceFrequency(&qpc_frequency);
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| -
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| -  int min_delta = 1e9;
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| -  LARGE_INTEGER qpc_last;
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| -  QueryPerformanceCounter(&qpc_last);
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| -  for (int i = 0; i < kNumIterations; ++i) {
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| -    LARGE_INTEGER qpc_now;
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| -    QueryPerformanceCounter(&qpc_now);
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| -    int delta = static_cast<int>(qpc_now.QuadPart - qpc_last.QuadPart);
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| -    if (delta != 0) {
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| -      min_delta = std::min(min_delta, delta);
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| -    }
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| -    qpc_last = qpc_now;
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| -
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| -    // Change cores every 10 iterations.
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| -    if (i % 10 == 0) {
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| -      DWORD_PTR old_mask = current_mask;
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| -      current_mask <<= 1;
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| -      while ((current_mask & default_mask) == 0) {
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| -        current_mask <<= 1;
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| -        if (!current_mask) {
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| -          current_mask = 1;
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| -        }
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| -        if (current_mask == old_mask) {
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| -          break;
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| -        }
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| -      }
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| -      if (!SetThreadAffinityMask(GetCurrentThread(), current_mask)) {
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| -        failed_to_change_cores = true;
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| -        break;
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| -      }
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| -    }
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| -  }
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| -
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| -  SetThreadAffinityMask(GetCurrentThread(), default_mask);
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| -  if (failed_to_change_cores) {
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| -    UMA_HISTOGRAM_ENUMERATION("WinTimeTicks.FailedToChangeCores",
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| -                              info->version(), base::win::VERSION_WIN_LAST);
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| -    return;
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| -  }
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| -
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| -  if (min_delta < 0) {
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| -    UMA_HISTOGRAM_ENUMERATION("WinTimeTicks.TickedBackwards", info->version(),
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| -                              base::win::VERSION_WIN_LAST);
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| -    return;
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| -  }
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| -
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| -  int min_delta_ns = static_cast<int>(
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| -      min_delta * (1e9 / qpc_frequency.QuadPart));
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| -  UMA_HISTOGRAM_CUSTOM_COUNTS("WinTimeTicks.MinResolutionNanoseconds",
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| -                              min_delta_ns, 1, 1000000, 50);
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| -
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| -  bool success = min_delta_ns <= 10000;
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| -  if (success) {
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| -    UMA_HISTOGRAM_ENUMERATION("WinTimeTicks.VersionSuccessful",
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| -                              info->version(), base::win::VERSION_WIN_LAST);
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| -  }
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| -}
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| -
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| -}  // namespace chrome
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| -
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| -#endif  // defined(OS_WIN)
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| 
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