citra/src/core/perf_stats.h

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// Copyright 2017 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include <array>
#include <atomic>
#include <chrono>
#include <mutex>
#include "common/common_types.h"
#include "common/thread.h"
namespace Core {
/**
* Class to manage and query performance/timing statistics. All public functions of this class are
* thread-safe unless stated otherwise.
*/
class PerfStats {
public:
explicit PerfStats(u64 title_id);
~PerfStats();
using Clock = std::chrono::high_resolution_clock;
struct Results {
/// System FPS (LCD VBlanks) in Hz
double system_fps;
/// Game FPS (GSP frame submissions) in Hz
double game_fps;
/// Walltime per system frame, in seconds, excluding any waits
double frametime;
/// Ratio of walltime / emulated time elapsed
double emulation_speed;
};
void BeginSystemFrame();
void EndSystemFrame();
void EndGameFrame();
Results GetAndResetStats(std::chrono::microseconds current_system_time_us);
/**
* Returns the Arthimetic Mean of all frametime values stored in the performance history.
*/
double GetMeanFrametime();
/**
* Gets the ratio between walltime and the emulated time of the previous system frame. This is
* useful for scaling inputs or outputs moving between the two time domains.
*/
double GetLastFrameTimeScale();
private:
std::mutex object_mutex{};
/// Title ID for the game that is running. 0 if there is no game running yet
u64 title_id{0};
/// Current index for writing to the perf_history array
size_t current_index{0};
/// Stores an hour of historical frametime data useful for processing and tracking performance
/// regressions with code changes.
std::array<double, 216000> perf_history = {};
/// Point when the cumulative counters were reset
Clock::time_point reset_point = Clock::now();
/// System time when the cumulative counters were reset
std::chrono::microseconds reset_point_system_us{0};
/// Cumulative duration (excluding v-sync/frame-limiting) of frames since last reset
Clock::duration accumulated_frametime = Clock::duration::zero();
/// Cumulative number of system frames (LCD VBlanks) presented since last reset
u32 system_frames = 0;
/// Cumulative number of game frames (GSP frame submissions) since last reset
u32 game_frames = 0;
/// Point when the previous system frame ended
Clock::time_point previous_frame_end = reset_point;
/// Point when the current system frame began
Clock::time_point frame_begin = reset_point;
/// Total visible duration (including frame-limiting, etc.) of the previous system frame
Clock::duration previous_frame_length = Clock::duration::zero();
};
class FrameLimiter {
public:
using Clock = std::chrono::high_resolution_clock;
void DoFrameLimiting(std::chrono::microseconds current_system_time_us);
/**
* Sets whether frame advancing is enabled or not.
* Note: The frontend must cancel frame advancing before shutting down in order
* to resume the emu_thread.
*/
void SetFrameAdvancing(bool value);
void AdvanceFrame();
private:
/// Emulated system time (in microseconds) at the last limiter invocation
std::chrono::microseconds previous_system_time_us{0};
/// Walltime at the last limiter invocation
Clock::time_point previous_walltime = Clock::now();
/// Accumulated difference between walltime and emulated time
std::chrono::microseconds frame_limiting_delta_err{0};
/// Whether to use frame advancing (i.e. frame by frame)
std::atomic_bool frame_advancing_enabled;
/// Event to advance the frame when frame advancing is enabled
Common::Event frame_advance_event;
};
} // namespace Core