From d44de3a9dcb7645a6442b2b51bcde7684b319861 Mon Sep 17 00:00:00 2001
From: Connor McLaughlin <stenzek@gmail.com>
Date: Thu, 14 Jan 2021 00:40:25 +1000
Subject: [PATCH] System: Use SetWaitableTimer() for throttling on Windows

---
 src/core/system.cpp | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/core/system.cpp b/src/core/system.cpp
index afa9b5f23..693e41069 100644
--- a/src/core/system.cpp
+++ b/src/core/system.cpp
@@ -1299,7 +1299,31 @@ void Throttle()
   else if (sleep_time >= MINIMUM_SLEEP_TIME)
   {
 #ifdef WIN32
-    Sleep(static_cast<u32>(sleep_time / 1000000));
+    static HANDLE throttle_timer;
+    static bool throttle_timer_created = false;
+    if (!throttle_timer_created)
+    {
+      throttle_timer_created = true;
+      throttle_timer = CreateWaitableTimer(nullptr, TRUE, nullptr);
+      if (throttle_timer)
+        std::atexit([]() { CloseHandle(throttle_timer); });
+      else
+        Log_ErrorPrintf("CreateWaitableTimer() failed, falling back to Sleep()");
+    }
+
+    if (throttle_timer)
+    {
+      LARGE_INTEGER due_time;
+      due_time.QuadPart = -static_cast<s64>(static_cast<u64>(sleep_time) / 100u);
+      if (SetWaitableTimer(throttle_timer, &due_time, 0, nullptr, nullptr, FALSE))
+        WaitForSingleObject(throttle_timer, INFINITE);
+      else
+        Log_ErrorPrintf("SetWaitableTimer() failed: %08X", GetLastError());
+    }
+    else
+    {
+      Sleep(static_cast<u32>(sleep_time / 1000000));
+    }
 #else
     const struct timespec ts = {0, static_cast<long>(sleep_time)};
     nanosleep(&ts, nullptr);