Add more accurate sleep function (well, not more accurate on Windows unfortunately)

Common/GPU/OpenGL/GLRenderManager.h

@@ -882,8 +882,6 @@ private:
 	std::mutex syncMutex_;
 	std::condition_variable syncCondVar_;
 
-	bool firstFrame_ = true;
-	bool vrRenderStarted_ = false;
 	bool syncDone_ = false;
 
 	GLDeleter deleter_;

Common/TimeUtil.cpp

@@ -253,8 +253,12 @@ double Instant::ElapsedSeconds() const {
 
 #endif
 
+#define SLEEP_LOG_ENABLED 0
+
 void sleep_ms(int ms, const char *reason) {
-	// INFO_LOG(Log::System, "Sleep %d ms: %s", ms, reason);
+#if SLEEP_LOG_ENABLED
+	INFO_LOG(Log::System, "Sleep %d ms: %s", ms, reason);
+#endif
 #ifdef _WIN32
 	Sleep(ms);
 #elif defined(HAVE_LIBNX)
@@ -266,10 +270,29 @@ void sleep_ms(int ms, const char *reason) {
 #endif
 }
 
-void sleep_precise(double seconds) {
+void sleep_us(int us, const char *reason) {
+#if SLEEP_LOG_ENABLED
+	INFO_LOG(Log::System, "Sleep %d us: %s", us, reason);
+#endif
+#ifdef _WIN32
+	Sleep(us / 1000);
+#elif defined(HAVE_LIBNX)
+	svcSleepThread(us * 1000);
+#elif defined(__EMSCRIPTEN__)
+	emscripten_sleep(us / 1000);
+#else
+	usleep(us);
+#endif
+}
+
+// This can be a little more expensive in some circumstances, so only use when necessary.
+void sleep_precise(double seconds, const char *reason) {
 	if (seconds <= 0.0) {
 		return;
 	}
+#if SLEEP_LOG_ENABLED
+	INFO_LOG(Log::System, "Sleep precise %f s: %s", seconds, reason);
+#endif
 #ifdef _WIN32
 	// Precise Windows sleep function from: https://github.com/blat-blatnik/Snippets/blob/main/precise_sleep.c
 	// Described in: https://blog.bearcats.nl/perfect-sleep-function/
@@ -347,7 +370,7 @@ void GetCurrentTimeFormatted(char formattedTime[13]) {
 // We don't even bother synchronizing this, it's fine if threads stomp a bit.
 static GMRng g_sleepRandom;
 
-void sleep_random(double minSeconds, double maxSeconds) {
+void sleep_random(double minSeconds, double maxSeconds, const char *reason) {
 	const double waitSeconds = minSeconds + (maxSeconds - minSeconds) * g_sleepRandom.F();
-	sleep_precise(waitSeconds);
+	sleep_precise(waitSeconds, reason);
 }

Common/TimeUtil.h

@@ -17,16 +17,17 @@ double from_time_raw_relative(uint64_t raw_time);
 // Seconds, Unix UTC time
 double time_now_unix_utc();
 
-// Sleep. Does not necessarily have millisecond granularity, especially on Windows.
+// Sleep for milliseconds. Does not necessarily have millisecond granularity, especially on Windows.
 // Requires a "reason" since sleeping generally should be very sparingly used. This
 // can be logged if desired to figure out where we're wasting time.
 void sleep_ms(int ms, const char *reason);
-
+// Sleep for microseconds. Does not necessarily have microsecond granularity, especially on Windows.
+void sleep_us(int us, const char *reason);
 // Precise sleep. Can consume a little bit of CPU on Windows at least.
-void sleep_precise(double seconds);
+void sleep_precise(double seconds, const char *reason);
 
 // Random sleep, used for debugging.
-void sleep_random(double minSeconds, double maxSeconds);
+void sleep_random(double minSeconds, double maxSeconds, const char *reason);
 
 // Yield. Signals that this thread is busy-waiting but wants to allow other hyperthreads to run.
 void yield();

Core/FrameTiming.cpp

@@ -39,7 +39,7 @@ FrameTiming g_frameTiming;
 void WaitUntil(double now, double timestamp, const char *reason) {
 #if 1
 	// Use precise timing.
-	sleep_precise(timestamp - now);
+	sleep_precise(timestamp - now, reason);
 #else
 
 #if PPSSPP_PLATFORM(WINDOWS)

Core/Util/PortManager.cpp

@@ -477,7 +477,7 @@ int upnpService(const unsigned int timeout) {
 	// Service Loop
 	while (upnpServiceRunning) {
 		// Sleep for 1ms for faster response if active, otherwise sleep longer (TODO: Improve on this).
-		sleep_ms(g_Config.bEnableUPnP ? 1 : 100, "upnp-poll");
+		sleep_ms(g_Config.bEnableUPnP ? 1 : 500, "upnp-poll");
 
 		// Attempts to reconnect if not connected yet or got disconnected
 		if (g_Config.bEnableUPnP && g_PortManager.GetInitState() == UPNP_INITSTATE_NONE) {

UI/NativeApp.cpp

@@ -1251,9 +1251,9 @@ void NativeFrame(GraphicsContext *graphicsContext) {
 		// Simple throttling to not burn the GPU in the menu.
 		// TODO: This is only necessary in MAILBOX or IMMEDIATE presentation modes.
 		double diffTime = time_now_d() - startTime;
-		int sleepTime = (int)(1000.0 / refreshRate) - (int)(diffTime * 1000.0);
-		if (sleepTime > 0)
-			sleep_ms(sleepTime, "fallback-throttle");
+		int sleepTimeUs = (int)(1000000 * ((1.0 / refreshRate) - diffTime));
+		if (sleepTimeUs > 0)
+			sleep_us(sleepTimeUs, "fallback-throttle");
 	}
 }