BlockingLoop: Yield to UI message pump while waiting.

Source/Android/jni/MainAndroid.cpp

@@ -148,6 +148,10 @@ void Host_ShowVideoConfig(void*, const std::string&)
 {
 }
 
+void Host_YieldToUI()
+{
+}
+
 static bool MsgAlert(const char* caption, const char* text, bool yes_no, int /*Style*/)
 {
   __android_log_print(ANDROID_LOG_ERROR, DOLPHIN_TAG, "%s:%s", caption, text);

Source/Core/Common/BlockingLoop.h

@@ -66,6 +66,33 @@ public:
     m_may_sleep.Set();
   }
 
+  // Wait for a complete payload run after the last Wakeup() call.
+  // This version will call a yield function every 100ms.
+  // If stopped, this returns immediately.
+  template <class Rep, class Period, typename Functor>
+  void WaitYield(const std::chrono::duration<Rep, Period>& rel_time, Functor yield_func)
+  {
+    // already done
+    if (IsDone())
+      return;
+
+    // notifying this event will only wake up one thread, so use a mutex here to
+    // allow only one waiting thread. And in this way, we get an event free wakeup
+    // but for the first thread for free
+    std::lock_guard<std::mutex> lk(m_wait_lock);
+
+    // Wait for the worker thread to finish.
+    while (!IsDone())
+    {
+      if (!m_done_event.WaitFor(rel_time))
+        yield_func();
+    }
+
+    // As we wanted to wait for the other thread, there is likely no work remaining.
+    // So there is no need for a busy loop any more.
+    m_may_sleep.Set();
+  }
+
   // Half start the worker.
   // So this object is in a running state and Wait() will block until the worker calls Run().
   // This may be called from any thread and is supposed to be called at least once before Wait() is

Source/Core/Core/Host.h

@@ -38,6 +38,7 @@ void Host_UpdateDisasmDialog();
 void Host_UpdateMainFrame();
 void Host_UpdateTitle(const std::string& title);
 void Host_ShowVideoConfig(void* parent, const std::string& backend_name);
+void Host_YieldToUI();
 
 // TODO (neobrain): Remove this from host!
 void* Host_GetRenderHandle();

Source/Core/DolphinQt2/Host.cpp

@@ -89,6 +89,9 @@ bool Host_RendererIsFullscreen()
 {
   return Host::GetInstance()->GetRenderFullscreen();
 }
+void Host_YieldToUI()
+{
+}
 
 // We ignore these, and their purpose should be questioned individually.
 // In particular, RequestRenderWindowSize, RequestFullscreen, and

Source/Core/DolphinWX/Main.cpp

@@ -10,6 +10,7 @@
 #include <wx/app.h>
 #include <wx/buffer.h>
 #include <wx/cmdline.h>
+#include <wx/evtloop.h>
 #include <wx/image.h>
 #include <wx/imagpng.h>
 #include <wx/intl.h>
@@ -547,3 +548,8 @@ void Host_ShowVideoConfig(void* parent, const std::string& backend_name)
     diag.ShowModal();
   }
 }
+
+void Host_YieldToUI()
+{
+  wxGetApp().GetMainLoop()->YieldFor(wxEVT_CATEGORY_UI);
+}

Source/Core/DolphinWX/MainNoGUI.cpp

@@ -161,6 +161,10 @@ void Host_ShowVideoConfig(void*, const std::string&)
 {
 }
 
+void Host_YieldToUI()
+{
+}
+
 #if HAVE_X11
 #include <X11/keysym.h>
 #include "DolphinWX/X11Utils.h"

Source/Core/VideoCommon/Fifo.cpp

@@ -18,6 +18,7 @@
 #include "Core/CoreTiming.h"
 #include "Core/HW/Memmap.h"
 #include "Core/HW/SystemTimers.h"
+#include "Core/Host.h"
 #include "Core/NetPlayProto.h"
 
 #include "VideoCommon/AsyncRequests.h"
@@ -94,7 +95,13 @@ void PauseAndLock(bool doLock, bool unpauseOnUnlock)
   {
     SyncGPU(SyncGPUReason::Other);
     EmulatorState(false);
-    FlushGpu();
+
+    const SConfig& param = SConfig::GetInstance();
+
+    if (!param.bCPUThread || s_use_deterministic_gpu_thread)
+      return;
+
+    s_gpu_mainloop.WaitYield(std::chrono::milliseconds(100), Host_YieldToUI);
   }
   else
   {

Source/UnitTests/TestUtils/StubHost.cpp

@@ -63,6 +63,9 @@ void Host_SetWiiMoteConnectionState(int)
 void Host_ShowVideoConfig(void*, const std::string&)
 {
 }
+void Host_YieldToUI()
+{
+}
 std::unique_ptr<cInterfaceBase> HostGL_CreateGLInterface()
 {
   return nullptr;