Add performance statistics to status bar

src/core/perf_stats.h

@@ -0,0 +1,43 @@
+// Copyright 2017 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <chrono>
+#include "common/common_types.h"
+
+namespace Core {
+
+class PerfStats {
+public:
+    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(u64 current_system_time_us);
+
+private:
+    Clock::time_point reset_point = Clock::now();
+
+    Clock::time_point frame_begin;
+    Clock::duration accumulated_frametime = Clock::duration::zero();
+    u64 reset_point_system_us = 0;
+    u32 system_frames = 0;
+    u32 game_frames = 0;
+};
+
+} // namespace Core