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. More...

const std::vector< size_t > &	GetIndices (CpuAffinity affinity) const
	Return the set of CPU indices for the requested CPU affinity. More...

Detailed Description

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

Note: This is visible for testing.

Definition at line 60 of file cpu_affinity.h.

Constructor & Destructor Documentation

◆ CPUSpeedTracker()

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

explicit

Definition at line 34 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);
    }
  }
 
  valid_ = true;
}

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 71 of file cpu_affinity.cc.

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

◆ 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 67 of file cpu_affinity.cc.

                                    {
  return valid_;
}

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