From 7c202ab4110ffdc39311e03938e78ce77fb54e8c Mon Sep 17 00:00:00 2001
From: Scott Mansell <phiren@gmail.com>
Date: Mon, 16 Jan 2023 13:45:13 +1300
Subject: [PATCH] Reset throttle on savestate load

---
 Source/Core/Core/CoreTiming.cpp | 21 ++++++++++++++++-----
 Source/Core/Core/CoreTiming.h   |  2 ++
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/Source/Core/Core/CoreTiming.cpp b/Source/Core/Core/CoreTiming.cpp
index eb7b537a61..d4c695b27f 100644
--- a/Source/Core/Core/CoreTiming.cpp
+++ b/Source/Core/Core/CoreTiming.cpp
@@ -101,8 +101,7 @@ void CoreTimingManager::Init()
   m_is_global_timer_sane = true;
 
   // Reset data used by the throttling system
-  m_throttle_last_cycle = 0;
-  m_throttle_deadline = Clock::now();
+  ResetThrottle(0);
 
   m_event_fifo_id = 0;
   m_ev_lost = RegisterEvent("_lost_event", &EmptyTimedCallback);
@@ -175,11 +174,17 @@ void CoreTimingManager::DoState(PointerWrap& p)
   });
   p.DoMarker("CoreTimingEvents");
 
-  // When loading from a save state, we must assume the Event order is random and meaningless.
-  // The exact layout of the heap in memory is implementation defined, therefore it is platform
-  // and library version specific.
   if (p.IsReadMode())
+  {
+    // When loading from a save state, we must assume the Event order is random and meaningless.
+    // The exact layout of the heap in memory is implementation defined, therefore it is platform
+    // and library version specific.
     std::make_heap(m_event_queue.begin(), m_event_queue.end(), std::greater<Event>());
+
+    // The stave state has changed the time, so our previous Throttle targets are invalid.
+    // Especially when global_time goes down; So we create a fake throttle update.
+    ResetThrottle(m_globals.global_timer);
+  }
 }
 
 // This should only be called from the CPU thread. If you are calling
@@ -382,6 +387,12 @@ void CoreTimingManager::Throttle(const s64 target_cycle)
   }
 }
 
+void CoreTimingManager::ResetThrottle(s64 cycle)
+{
+  m_throttle_last_cycle = cycle;
+  m_throttle_deadline = Clock::now();
+}
+
 TimePoint CoreTimingManager::GetCPUTimePoint(s64 cyclesLate) const
 {
   return TimePoint(std::chrono::duration_cast<DT>(DT_s(m_globals.global_timer - cyclesLate) /
diff --git a/Source/Core/Core/CoreTiming.h b/Source/Core/Core/CoreTiming.h
index 1a860c5fa5..6bf5f908c3 100644
--- a/Source/Core/Core/CoreTiming.h
+++ b/Source/Core/Core/CoreTiming.h
@@ -185,6 +185,8 @@ private:
   s64 m_throttle_clock_per_sec;
   s64 m_throttle_min_clock_per_sleep;
 
+  void ResetThrottle(s64 cycle);
+
   int DowncountToCycles(int downcount) const;
   int CyclesToDowncount(int cycles) const;
 };