From 8b29e73f962d718bd1b3cf3794e5b0b47702b653 Mon Sep 17 00:00:00 2001
From: Jamie Reece Wilson <me@reece.sx>
Date: Mon, 4 Mar 2024 13:07:49 +0000
Subject: [PATCH] [*] Switch over to mapped cpuset ids as opposed to the
 ((groupIndex + 1ull) * 0x100ull) + logicalProcessorIndex approximation

---
 Include/Aurora/HWInfo/CpuBitId.NT.inl | 7 +++++++
 Source/HWInfo/AuCpuInfo.NT.cpp        | 8 ++++++++
 2 files changed, 15 insertions(+)

diff --git a/Include/Aurora/HWInfo/CpuBitId.NT.inl b/Include/Aurora/HWInfo/CpuBitId.NT.inl
index c2d1ef24..cc1727fe 100644
--- a/Include/Aurora/HWInfo/CpuBitId.NT.inl
+++ b/Include/Aurora/HWInfo/CpuBitId.NT.inl
@@ -9,6 +9,8 @@
 
 namespace Aurora::HWInfo
 {
+    extern AUKN_SYM AuUInt32 gWin32CPUSetLookupTable[512];
+
     AuList<unsigned long> CpuBitId::ToCpuSets() const
     {
         AuList<unsigned long> ret;
@@ -16,10 +18,15 @@ namespace Aurora::HWInfo
         AuUInt8 index {};
         while (CpuBitScanForward(index, index))
         {
+        #if defined(AURORA_RUNTIME_USE_FAST_CPUSETS)
             unsigned long logicalProcessorIndex = index % 64;
             unsigned long groupIndex = index / 64;
             ret.push_back(((groupIndex + 1ull) * 0x100ull) + logicalProcessorIndex);
             index++;
+        #else
+            ret.push_back(gWin32CPUSetLookupTable[index]);
+            index++;
+        #endif
         }
 
         return ret;
diff --git a/Source/HWInfo/AuCpuInfo.NT.cpp b/Source/HWInfo/AuCpuInfo.NT.cpp
index f959705b..a535ecc4 100644
--- a/Source/HWInfo/AuCpuInfo.NT.cpp
+++ b/Source/HWInfo/AuCpuInfo.NT.cpp
@@ -16,6 +16,8 @@
 
 namespace Aurora::HWInfo
 {
+    AUKN_SYM AuUInt32 gWin32CPUSetLookupTable[512] {};
+
     static bool SetWindows10CpuSetInfoSlow()
     {
         SYSTEM_CPU_SET_INFORMATION cpuSetInfo[128];
@@ -98,9 +100,15 @@ namespace Aurora::HWInfo
             AuUInt8 id = AuUInt8(cpuSetInfo[i].CpuSet.LogicalProcessorIndex /*no greater than 64*/ + (cpuSetInfo[i].CpuSet.Group * 64));
             auto cpuId = CpuBitId(id);
 
+        #if defined(AURORA_RUNTIME_USE_FAST_CPUSETS)
             auto sets = cpuId.ToCpuSets();
             SysAssert(sets.size() == 1);
             SysAssert(sets[0] == cpuSetInfo[i].CpuSet.Id);
+        #endif
+
+            // Future proofing for later NT versions 
+            SysAssert(id < AuArraySize(gWin32CPUSetLookupTable));
+            gWin32CPUSetLookupTable[id] = cpuSetInfo[i].CpuSet.Id;
 
             idx.server.push_back(AuMakePair(cpuSetInfo[i].CpuSet.EfficiencyClass, cpuId));
             idx.low.push_back(id);