chromium/base/power_monitor/cpu_frequency_utils.h

// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_POWER_MONITOR_CPU_FREQUENCY_UTILS_H_
#define BASE_POWER_MONITOR_CPU_FREQUENCY_UTILS_H_

#include <optional>

#include "base/base_export.h"
#include "base/time/time.h"
#include "base/values.h"

namespace base {

struct BASE_EXPORT CpuFrequencyInfo { … };

struct BASE_EXPORT CpuThroughputEstimationResult { … };

// Returns the estimated CPU frequency of the current core by executing a tight
// loop of predictable assembly instructions. The estimated frequency should be
// proportional to and about the same magnitude as the real CPU frequency,
// although it is possible for the code to be migrated/descheduled during the
// execution of this function. The measurement should be long enough to avoid
// Turbo Boost effect (~3ms) and be low enough to stay within the operating
// system scheduler quantum (~100ms).
// The return value is the estimated CPU frequency, in Hz.
BASE_EXPORT double EstimateCpuFrequency();
BASE_EXPORT std::optional<CpuThroughputEstimationResult>
EstimateCpuThroughput();

// Populates and returns a `CpuFrequencyInfo` struct with information from the
// current CPU core.
BASE_EXPORT CpuFrequencyInfo GetCpuFrequencyInfo();

#if BUILDFLAG(IS_WIN)
BASE_EXPORT void GenerateCpuInfoForTracingMetadata(base::Value::Dict* metadata);
#endif
}  // namespace base

#endif  // BASE_POWER_MONITOR_CPU_FREQUENCY_UTILS_H_