From 3747fb7c6ff1e1a2ad5a37a2b0ead2984c958268 Mon Sep 17 00:00:00 2001
From: Jamie Reece Wilson <me@reece.sx>
Date: Tue, 22 Aug 2023 09:55:05 +0100
Subject: [PATCH] [+] ThreadingConfig::uUWPNanosecondEmulationMaxYields [+]
 ThreadingConfig::bUWPNanosecondEmulationCheckFirst

---
 Include/Aurora/Runtime.hpp           |  2 ++
 Source/Threading/AuWakeOnAddress.cpp | 14 +++++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Include/Aurora/Runtime.hpp b/Include/Aurora/Runtime.hpp
index 3179582d..eef0c24f 100644
--- a/Include/Aurora/Runtime.hpp
+++ b/Include/Aurora/Runtime.hpp
@@ -362,6 +362,8 @@ namespace Aurora
         AuUInt64 bPreferLinuxCondMutexSpinTryLock : 1 { true  };
         AuUInt64 bPreferEmulatedWakeOnAddress     : 1 { false };
         AuUInt64 bPreferRWLockReadLockSpin        : 1 { true  };
+        AuUInt64 bUWPNanosecondEmulationCheckFirst: 1 { false};
+        AuUInt64 uUWPNanosecondEmulationMaxYields : 7 { 12 };
     };
 
     struct DummyConfig
diff --git a/Source/Threading/AuWakeOnAddress.cpp b/Source/Threading/AuWakeOnAddress.cpp
index e7705caf..ef7bcfd0 100644
--- a/Source/Threading/AuWakeOnAddress.cpp
+++ b/Source/Threading/AuWakeOnAddress.cpp
@@ -582,6 +582,9 @@ namespace Aurora::Threading
                 uRelativeNanoseconds = iDelta;
             }
 
+            auto uMaxSwitches = gRuntimeConfig.threadingConfig.uUWPNanosecondEmulationMaxYields;
+            auto bUWPNanosecondEmulationCheckFirst = gRuntimeConfig.threadingConfig.bUWPNanosecondEmulationCheckFirst;
+
             // LockN(<1MS) on a platform without that resolution of yielding... damn
             auto uMS = AuNSToMS<AuUInt32>(uRelativeNanoseconds);
             if (!uMS)
@@ -596,6 +599,7 @@ namespace Aurora::Threading
                 }
 
                 // second: yield
+                unsigned uLimit {};
                 do
                 {
                     if (!expect.Compare(pTargetAddress))
@@ -604,6 +608,14 @@ namespace Aurora::Threading
                     }
                  
                     AuThreading::ContextYield();
+
+                    if (bUWPNanosecondEmulationCheckFirst)
+                    {
+                        if (uLimit++ > uMaxSwitches)
+                        {
+                            break;
+                        }
+                    }
                 }
                 while (uAbsTimeSteadyClock > AuTime::SteadyClockNS()); // ...until times up
             }
@@ -638,7 +650,7 @@ namespace Aurora::Threading
                     if (!uMS)
                     {
                         // burn off any remainder cycles by switching contexts (this isnt a very long time usually)
-                        if (uLimit++ < 4)
+                        if (uLimit++ < uMaxSwitches)
                         {
                             AuThreading::ContextYield();
                         }