ProcessorAffinity Support

SS14.Watchdog/Components/ProcessManagement/ProcessManagerBasic.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Diagnostics;
 using System.IO;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Dapper;
@@ -9,6 +10,7 @@
 using Microsoft.Extensions.Options;
 using SS14.Watchdog.Components.DataManagement;
 using SS14.Watchdog.Components.ServerManagement;
+using SS14.Watchdog.Configuration;
 
 namespace SS14.Watchdog.Components.ProcessManagement;
 
@@ -69,6 +71,14 @@ public Task<IProcessHandle> StartServer(IServerInstance instance, ProcessStartDa
 
             if (process == null)
                 throw new Exception("No process was started??");
+
+            if (instance.CpuCores != null)
+            {
+                var affinity = instance.CpuCores.Aggregate(0L, (mask, core) => mask | (1L << core));
+                process.ProcessorAffinity = (IntPtr)affinity;
+                _logger.LogDebug("Set processor affinity to {Affinity} for process {Pid}",
+                    affinity, process.Id);
+            }
         }
         catch (Exception e)
         {

SS14.Watchdog/Components/ServerManagement/IServerInstance.cs

@@ -1,3 +1,4 @@
+using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -36,6 +37,13 @@ public interface IServerInstance
         /// </summary>
         string InstanceDir { get; }
 
+        /// <summary>
+        ///     List of CPU cores to use for the server process.
+        ///     If set, the process will be restricted to run only on the specified CPU cores.
+        ///     Example: [0, 1] means use cores 0 and 1.
+        /// </summary>
+        IReadOnlyList<int>? CpuCores { get; }
+
         /// <summary>
         ///     Server has sent a ping to the watchdog confirming that it is, in fact, still alive.
         /// </summary>

SS14.Watchdog/Components/ServerManagement/ServerInstance.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Net.Http;
 using System.Security.Cryptography;
@@ -63,6 +64,8 @@ public sealed partial class ServerInstance : IServerInstance
 
         private IProcessHandle? _runningServer;
 
+        public IReadOnlyList<int>? CpuCores => _instanceConfig.CpuCores;
+
         public ServerInstance(string key,
             InstanceConfiguration instanceConfig,
             IConfiguration configuration,

SS14.Watchdog/Configuration/InstanceConfiguration.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 using System.Runtime.InteropServices;
 using JetBrains.Annotations;
 using Microsoft.Diagnostics.NETCore.Client;
@@ -47,5 +48,12 @@ public sealed class InstanceConfiguration
         /// </summary>
         [UsedImplicitly]
         public Dictionary<string, string> EnvironmentVariables { get; set; } = new();
+
+        /// <summary>
+        /// List of CPU cores to use for the server process.
+        /// If set, the process will be restricted to run only on the specified CPU cores.
+        /// Example: [0, 1] means use cores 0 and 1.
+        /// </summary>
+        public List<int>? CpuCores { get; set; }
     }
 }