yuzu/src/core/perf_stats.h
ameerj 5bef54618a perf_stats: Rework FPS counter to be more accurate
The FPS counter was based on metrics in the nvdisp swapbuffers call. This metric would be accurate if the gpu thread/renderer were synchronous with the nvdisp service, but that's no longer the case.

This commit moves the frame counting responsibility onto the concrete renderers after their frame draw calls. Resulting in more meaningful metrics.
The displayed FPS is now made up of the average framerate between the previous and most recent update, in order to avoid distracting FPS counter updates when framerate is oscillating between close values.

The status bar update frequency was also changed from 2 seconds to 500ms.
2021-05-15 20:34:20 -04:00

105 lines
3.4 KiB
C++

// 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 <cstddef>
#include <mutex>
#include "common/common_types.h"
namespace Core {
struct PerfStatsResults {
/// System FPS (LCD VBlanks) in Hz
double system_fps;
/// Average game FPS (GPU frame renders) in Hz
double average_game_fps;
/// Walltime per system frame, in seconds, excluding any waits
double frametime;
/// Ratio of walltime / emulated time elapsed
double emulation_speed;
};
/**
* 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;
void BeginSystemFrame();
void EndSystemFrame();
void EndGameFrame();
PerfStatsResults GetAndResetStats(std::chrono::microseconds current_system_time_us);
/**
* Returns the arithmetic mean of all frametime values stored in the performance history.
*/
double GetMeanFrametime() const;
/**
* 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() const;
private:
mutable 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
std::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
std::atomic<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();
/// Previously computed fps
double previous_fps = 0;
};
class FrameLimiter {
public:
using Clock = std::chrono::high_resolution_clock;
void DoFrameLimiting(std::chrono::microseconds current_system_time_us);
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};
};
} // namespace Core