From 62cc3cfbf358e7951e99523eb13644c3c9ad36ba Mon Sep 17 00:00:00 2001
From: ramapcsx2 <ramapcsx2@96395faa-99c1-11dd-bbfe-3dabce05a288>
Date: Sun, 9 Aug 2009 18:38:10 +0000
Subject: [PATCH] Workaround a problem with thread affinities. Should fix some
 slowness issues, mainly on AMD cpus.

git-svn-id: http://pcsx2.googlecode.com/svn/trunk@1614 96395faa-99c1-11dd-bbfe-3dabce05a288
---
 pcsx2/x86/ix86/ix86_cpudetect.cpp | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/pcsx2/x86/ix86/ix86_cpudetect.cpp b/pcsx2/x86/ix86/ix86_cpudetect.cpp
index 409f3cf64d..70bad69230 100644
--- a/pcsx2/x86/ix86/ix86_cpudetect.cpp
+++ b/pcsx2/x86/ix86/ix86_cpudetect.cpp
@@ -216,6 +216,19 @@ static void SetSingleAffinity()
 #endif
 }
 
+static void UnSetSingleAffinity()
+{
+#ifdef _WINDOWS_
+	HANDLE s_threadId = GetCurrentThread();
+	s_oldmask = SetThreadAffinityMask( s_threadId, 0xFFFFFFFF );
+
+	if( s_oldmask == ERROR_INVALID_PARAMETER )
+	{
+		Console::Notice("CpuDetect: UnSetThreadAffinityMask failed...");
+	}
+#endif
+}
+
 //////////////////////////////////////////////////////////////////////////////////////////
 //
 s64 CPUSpeedHz( u64 time )
@@ -489,5 +502,9 @@ void cpudetectInit()
 
 	// This will assign values into cpuinfo.LogicalCores and PhysicalCores
 	Threading::CountLogicalCores( LogicalCoresPerPhysicalCPU, PhysicalCoresPerPhysicalCPU );
+
+	// Undo previous SetSingleAffinity() here, so the host OS can handle load distribution
+	// (up to 25% faster on athlonx2, about 5% faster on core2)
+	UnSetSingleAffinity();
 }