Added NoGCRegion feature

Libraries/SPTarkov.Server.Assets/SPT_Data/configs/core.json

@@ -5,6 +5,9 @@
   "profileSaveIntervalSeconds": 15,
   "sptFriendNickname": "SPT",
   "allowProfileWipe": true,
+  "enableNoGCRegions": true,
+  "noGCRegionMaxMemoryGB": 4,
+  "noGCRegionMaxLOHMemoryGB": 3,
   "bsgLogging": {
     "verbosity": 6,
     "sendToServer": false

Libraries/SPTarkov.Server.Core/Models/Spt/Config/CoreConfig.cs

@@ -42,6 +42,50 @@ public record CoreConfig : BaseConfig
     [JsonPropertyName("features")]
     public required ServerFeatures Features { get; set; }
 
+    [JsonPropertyName("enableNoGCRegions")]
+    // ReSharper disable once InconsistentNaming
+    public required bool EnableNoGCRegions { get; set; }
+
+    // ReSharper disable once InconsistentNaming
+    private int _noGCRegionMaxMemoryGB = 4;
+
+    [JsonPropertyName("noGCRegionMaxMemoryGB")]
+    // ReSharper disable once InconsistentNaming
+    public required int NoGCRegionMaxMemoryGB
+    {
+        get => _noGCRegionMaxMemoryGB;
+        set
+        {
+            if (value <= 0)
+            {
+                throw new ArgumentOutOfRangeException(
+                    $"Invalid value: {nameof(NoGCRegionMaxMemoryGB)}: {value}. Must be greater than zero."
+                );
+            }
+            _noGCRegionMaxMemoryGB = value;
+        }
+    }
+
+    // ReSharper disable once InconsistentNaming
+    private int _noGCRegionMaxLOHMemoryGB = 3;
+
+    [JsonPropertyName("noGCRegionMaxLOHMemoryGB")]
+    // ReSharper disable once InconsistentNaming
+    public required int NoGCRegionMaxLOHMemoryGB
+    {
+        get => _noGCRegionMaxLOHMemoryGB;
+        set
+        {
+            if (value <= 0)
+            {
+                throw new ArgumentOutOfRangeException(
+                    $"Invalid value {nameof(NoGCRegionMaxLOHMemoryGB)}: {value}. Must be greater than zero."
+                );
+            }
+            _noGCRegionMaxLOHMemoryGB = value;
+        }
+    }
+
     /// <summary>
     ///     Commit hash build server was created from
     /// </summary>

SPTarkov.Server/Program.cs

@@ -1,5 +1,6 @@
 using System.Net;
 using System.Net.Sockets;
+using System.Runtime;
 using System.Runtime.InteropServices;
 using System.Security.Authentication;
 using System.Text;
@@ -147,12 +148,9 @@ private static void ConfigureWebApp(WebApplication app)
 
         app.UseMiddleware<SptLoggerMiddleware>();
 
-        app.Use(
-            async (HttpContext context, RequestDelegate next) =>
-            {
-                await context.RequestServices.GetRequiredService<HttpServer>().HandleRequest(context, next);
-            }
-        );
+        app.UseNoGCRegions();
+
+        app.Use(async (context, next) => await context.RequestServices.GetRequiredService<HttpServer>().HandleRequest(context, next));
 
         app.UseSptBlazor();
     }

SPTarkov.Server/Services/NoGCRegionMiddleware.cs

@@ -0,0 +1,80 @@
+using System.Runtime;
+using SPTarkov.Server.Core.Models.Spt.Config;
+using SPTarkov.Server.Core.Servers;
+
+namespace SPTarkov.Server.Services;
+
+// ReSharper disable once InconsistentNaming
+public class NoGCRegionMiddleware(RequestDelegate next)
+{
+    private static long _activeRequests;
+
+    private static bool OtherRequestsActive
+    {
+        get
+        {
+            return Interlocked.Read(ref _activeRequests) > 1;
+        }
+    }
+
+    public async Task InvokeAsync(HttpContext context)
+    {
+        Interlocked.Increment(ref _activeRequests);
+
+        var config = context.RequestServices.GetRequiredService<ConfigServer>().GetConfig<CoreConfig>();
+
+        // if no other requests are running, start the no GC region, otherwise dont start it
+        if (!OtherRequestsActive)
+        {
+            if (config.EnableNoGCRegions && GCSettings.LatencyMode != GCLatencyMode.NoGCRegion)
+            {
+                try
+                {
+                    GC.TryStartNoGCRegion(
+                        1024L * 1024L * 1024L * config.NoGCRegionMaxMemoryGB,
+                        1024L * 1024L * 1024L * config.NoGCRegionMaxLOHMemoryGB,
+                        true
+                    );
+                }
+                catch (Exception)
+                {
+                    // ignored, we keep going
+                }
+            }
+        }
+        try
+        {
+            await next(context);
+        }
+        finally
+        {
+            Interlocked.Decrement(ref _activeRequests);
+        }
+
+        // if no other requests are running, end the no GC region, otherwise dont stop it as other requests need it still
+        if (!OtherRequestsActive)
+        {
+            if (config.EnableNoGCRegions && GCSettings.LatencyMode == GCLatencyMode.NoGCRegion)
+            {
+                try
+                {
+                    GC.EndNoGCRegion();
+                }
+                catch (Exception)
+                {
+                    // ignored, we dont care about handling this
+                }
+            }
+        }
+    }
+}
+
+// ReSharper disable once InconsistentNaming
+public static class NoGCRegionMiddlewareExtensions
+{
+    // ReSharper disable once InconsistentNaming
+    public static IApplicationBuilder UseNoGCRegions(this IApplicationBuilder builder)
+    {
+        return builder.UseMiddleware<NoGCRegionMiddleware>();
+    }
+}