fml::CPUSpeedTracker Class Reference

A class that computes the correct CPU indices for a requested CPU affinity. More...

#include <cpu_affinity.h>

Public Member Functions
	CPUSpeedTracker (std::vector< CpuIndexAndSpeed > data)
bool	IsValid () const
	The class is valid if it has more than one CPU index and a distinct set of efficiency or performance CPUs.
const std::vector< size_t > &	GetIndices (CpuAffinity affinity) const
	Return the set of CPU indices for the requested CPU affinity.

Detailed Description

A class that computes the correct CPU indices for a requested CPU affinity.

Note

This is visible for testing.

Definition at line 64 of file cpu_affinity.h.

Constructor & Destructor Documentation

CPUSpeedTracker()

fml::CPUSpeedTracker::CPUSpeedTracker ( std::vector< CpuIndexAndSpeed >  data )

explicit

Definition at line 35 of file cpu_affinity.cc.

    : cpu_speeds_(std::move(data)) {
  std::optional<int64_t> max_speed = std::nullopt;
  std::optional<int64_t> min_speed = std::nullopt;
  for (const auto& data : cpu_speeds_) {
    if (!max_speed.has_value() || data.speed > max_speed.value()) {
      max_speed = data.speed;
    }
    if (!min_speed.has_value() || data.speed < min_speed.value()) {
      min_speed = data.speed;
    }
  }
  if (!max_speed.has_value() || !min_speed.has_value() ||
      min_speed.value() == max_speed.value()) {
    return;
  }
  const int64_t max_speed_value = max_speed.value();
  const int64_t min_speed_value = min_speed.value();
 
  for (const auto& data : cpu_speeds_) {
    if (data.speed == max_speed_value) {
      performance_.push_back(data.index);
    } else {
      not_performance_.push_back(data.index);
    }
    if (data.speed == min_speed_value) {
      efficiency_.push_back(data.index);
    } else {
      not_efficiency_.push_back(data.index);
    }
  }
 
  valid_ = true;
}

References data.

Member Function Documentation

GetIndices()

const std::vector< size_t > & fml::CPUSpeedTracker::GetIndices

(

CpuAffinity

affinity

)

const

Return the set of CPU indices for the requested CPU affinity.

   If the tracker is valid, this will always return a non-empty set. 

Definition at line 74 of file cpu_affinity.cc.

                                {
  switch (affinity) {
    case CpuAffinity::kPerformance:
      return performance_;
    case CpuAffinity::kEfficiency:
      return efficiency_;
    case CpuAffinity::kNotPerformance:
      return not_performance_;
    case CpuAffinity::kNotEfficiency:
      return not_efficiency_;
  }
}

References fml::kEfficiency, fml::kNotEfficiency, fml::kNotPerformance, and fml::kPerformance.

Referenced by fml::AndroidEfficiencyCoreCount(), and fml::AndroidRequestAffinity().

IsValid()

bool fml::CPUSpeedTracker::IsValid

(

)

const

The class is valid if it has more than one CPU index and a distinct set of efficiency or performance CPUs.

If all CPUs are the same speed this returns false, and all requests to set affinity are ignored.

Definition at line 70 of file cpu_affinity.cc.

                                    {
  return valid_;
}

Referenced by fml::SetUpCPUTracker().

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The documentation for this class was generated from the following files:

• fml/cpu_affinity.h
• fml/cpu_affinity.cc