yuzu/src/core/perf_stats.cpp
Lioncash 781ab8407b general: Use deducation guides for std::lock_guard and std::unique_lock
Since C++17, the introduction of deduction guides for locking facilities
means that we no longer need to hardcode the mutex type into the locks
themselves, making it easier to switch mutex types, should it ever be
necessary in the future.
2019-04-01 12:53:47 -04:00

110 lines
3.6 KiB
C++

// Copyright 2017 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <algorithm>
#include <chrono>
#include <mutex>
#include <thread>
#include "common/math_util.h"
#include "core/perf_stats.h"
#include "core/settings.h"
using namespace std::chrono_literals;
using DoubleSecs = std::chrono::duration<double, std::chrono::seconds::period>;
using std::chrono::duration_cast;
using std::chrono::microseconds;
namespace Core {
void PerfStats::BeginSystemFrame() {
std::lock_guard lock{object_mutex};
frame_begin = Clock::now();
}
void PerfStats::EndSystemFrame() {
std::lock_guard lock{object_mutex};
auto frame_end = Clock::now();
accumulated_frametime += frame_end - frame_begin;
system_frames += 1;
previous_frame_length = frame_end - previous_frame_end;
previous_frame_end = frame_end;
}
void PerfStats::EndGameFrame() {
std::lock_guard lock{object_mutex};
game_frames += 1;
}
PerfStatsResults PerfStats::GetAndResetStats(microseconds current_system_time_us) {
std::lock_guard lock{object_mutex};
const auto now = Clock::now();
// Walltime elapsed since stats were reset
const auto interval = duration_cast<DoubleSecs>(now - reset_point).count();
const auto system_us_per_second = (current_system_time_us - reset_point_system_us) / interval;
PerfStatsResults results{};
results.system_fps = static_cast<double>(system_frames) / interval;
results.game_fps = static_cast<double>(game_frames) / interval;
results.frametime = duration_cast<DoubleSecs>(accumulated_frametime).count() /
static_cast<double>(system_frames);
results.emulation_speed = system_us_per_second.count() / 1'000'000.0;
// Reset counters
reset_point = now;
reset_point_system_us = current_system_time_us;
accumulated_frametime = Clock::duration::zero();
system_frames = 0;
game_frames = 0;
return results;
}
double PerfStats::GetLastFrameTimeScale() {
std::lock_guard lock{object_mutex};
constexpr double FRAME_LENGTH = 1.0 / 60;
return duration_cast<DoubleSecs>(previous_frame_length).count() / FRAME_LENGTH;
}
void FrameLimiter::DoFrameLimiting(microseconds current_system_time_us) {
if (!Settings::values.use_frame_limit) {
return;
}
auto now = Clock::now();
const double sleep_scale = Settings::values.frame_limit / 100.0;
// Max lag caused by slow frames. Shouldn't be more than the length of a frame at the current
// speed percent or it will clamp too much and prevent this from properly limiting to that
// percent. High values means it'll take longer after a slow frame to recover and start
// limiting
const microseconds max_lag_time_us = duration_cast<microseconds>(
std::chrono::duration<double, std::chrono::microseconds::period>(25ms / sleep_scale));
frame_limiting_delta_err += duration_cast<microseconds>(
std::chrono::duration<double, std::chrono::microseconds::period>(
(current_system_time_us - previous_system_time_us) / sleep_scale));
frame_limiting_delta_err -= duration_cast<microseconds>(now - previous_walltime);
frame_limiting_delta_err =
std::clamp(frame_limiting_delta_err, -max_lag_time_us, max_lag_time_us);
if (frame_limiting_delta_err > microseconds::zero()) {
std::this_thread::sleep_for(frame_limiting_delta_err);
auto now_after_sleep = Clock::now();
frame_limiting_delta_err -= duration_cast<microseconds>(now_after_sleep - now);
now = now_after_sleep;
}
previous_system_time_us = current_system_time_us;
previous_walltime = now;
}
} // namespace Core