Add processor affinity argument for Ares

ClientGUI/GameProcessLogic.cs

@@ -1,13 +1,17 @@
 using System;
 using System.Diagnostics;
+using System.Globalization;
 using System.IO;
 using System.Runtime.InteropServices;
+using System.Threading;
+
 using ClientCore;
-using Rampastring.Tools;
+using ClientCore.Enums;
+using ClientCore.Extensions;
 using ClientCore.INIProcessing;
-using System.Threading;
+
+using Rampastring.Tools;
 using Rampastring.XNAUI;
-using ClientCore.Extensions;
 
 namespace ClientGUI
 {
@@ -25,6 +29,35 @@ public static class GameProcessLogic
         public static bool UseQres { get; set; }
         public static bool SingleCoreAffinity { get; set; }
 
+        public static bool GetProcessorAffinityValue(out int affinity)
+        {
+            if (!(RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || RuntimeInformation.IsOSPlatform(OSPlatform.Linux)))
+            {
+                affinity = 0;
+                return false;
+            }
+
+            if (Environment.ProcessorCount <= 1)
+            {
+                affinity = 1; // Only one CPU core available
+                return true;
+            }
+
+
+            if (SingleCoreAffinity)
+            {
+                affinity = 2; // Use only CPU 1
+                return true;
+            }
+            else
+            {
+                int maximumCpuCountPerProcessorGroup = 64;
+                int cpuCount = Math.Min(Environment.ProcessorCount, maximumCpuCountPerProcessorGroup);
+                affinity = (1 << cpuCount) - 2; // All but CPU 0
+                return true;
+            }
+        }
+
         /// <summary>
         /// Starts the main game process.
         /// </summary>
@@ -83,6 +116,8 @@ public static void StartGameProcess(WindowManager windowManager)
 
             GameProcessStarting?.Invoke();
 
+            bool overrideProcessorAffinity = GetProcessorAffinityValue(out int processorAffinity);
+
             if (UserINISettings.Instance.WindowedMode && UseQres && RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
             {
                 Logger.Log("Windowed mode is enabled - using QRes.");
@@ -112,8 +147,8 @@ public static void StartGameProcess(WindowManager windowManager)
                     return;
                 }
 
-                if (Environment.ProcessorCount > 1 && SingleCoreAffinity)
-                    QResProcess.ProcessorAffinity = (IntPtr)2;
+                if (overrideProcessorAffinity)
+                    QResProcess.ProcessorAffinity = (IntPtr)processorAffinity;
             }
             else
             {
@@ -124,6 +159,12 @@ public static void StartGameProcess(WindowManager windowManager)
                 else
                     arguments = additionalExecutableName + "-SPAWN";
 
+                if (overrideProcessorAffinity && ClientConfiguration.Instance.ClientGameType == ClientType.Ares)
+                {
+                    // Ares defaults to use CPU 0 exclusively, unless explicitly overridden.
+                    arguments += " " + "-AFFINITY:" + processorAffinity.ToString(CultureInfo.InvariantCulture);
+                }
+
                 FileInfo gameFileInfo = SafePath.GetFile(ProgramConstants.GamePath, gameExecutableName);
 
                 var gameProcess = new Process();
@@ -151,11 +192,8 @@ public static void StartGameProcess(WindowManager windowManager)
                     return;
                 }
 
-                if ((RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
-                    && Environment.ProcessorCount > 1 && SingleCoreAffinity)
-                {
-                    gameProcess.ProcessorAffinity = (IntPtr)2;
-                }
+                if (overrideProcessorAffinity)
+                    gameProcess.ProcessorAffinity = (IntPtr)processorAffinity;
             }
 
             GameProcessStarted?.Invoke();