From db1e85e69ddf84aa24e9f99782eb7765a3ba0048 Mon Sep 17 00:00:00 2001
From: Pieter-Jan Briers <pieterjan.briers+git@gmail.com>
Date: Mon, 5 Dec 2022 00:44:50 +0100
Subject: [PATCH] Warmup system to speed up startup.

---
 Robust.Client/ClientWarmup.cs                 | 28 +++++++++++++++++++
 .../GameController.Standalone.cs              |  2 ++
 Robust.Server/Program.cs                      |  2 ++
 Robust.Server/ServerWarmup.cs                 | 20 +++++++++++++
 Robust.Shared/Resources/RsiLoading.cs         |  6 ++++
 Robust.Shared/SharedWarmup.cs                 | 21 ++++++++++++++
 6 files changed, 79 insertions(+)
 create mode 100644 Robust.Client/ClientWarmup.cs
 create mode 100644 Robust.Server/ServerWarmup.cs
 create mode 100644 Robust.Shared/SharedWarmup.cs

diff --git a/Robust.Client/ClientWarmup.cs b/Robust.Client/ClientWarmup.cs
new file mode 100644
index 0000000000..57ce11d91e
--- /dev/null
+++ b/Robust.Client/ClientWarmup.cs
@@ -0,0 +1,28 @@
+using System.Threading.Tasks;
+using Robust.Shared;
+using Robust.Shared.Resources;
+using SixLabors.ImageSharp;
+
+namespace Robust.Client;
+
+/// <summary>
+/// Logic for "warming up" things like slow static constructors concurrently.
+/// </summary>
+internal static class ClientWarmup
+{
+    public static void RunWarmup()
+    {
+        Task.Run(WarmupCore);
+    }
+
+    private static void WarmupCore()
+    {
+        // Get ImageSharp loaded.
+        _ = Configuration.Default;
+
+        SharedWarmup.WarmupCore();
+
+        // Preload the JSON loading code.
+        RsiLoading.Warmup();
+    }
+}
diff --git a/Robust.Client/GameController/GameController.Standalone.cs b/Robust.Client/GameController/GameController.Standalone.cs
index c89099a2a4..550e2ff49b 100644
--- a/Robust.Client/GameController/GameController.Standalone.cs
+++ b/Robust.Client/GameController/GameController.Standalone.cs
@@ -45,6 +45,8 @@ namespace Robust.Client
 
         private static void ParsedMain(CommandLineArgs args, bool contentStart, IMainArgs? loaderArgs, GameControllerOptions options)
         {
+            ClientWarmup.RunWarmup();
+
             var deps = IoCManager.InitThread();
             var mode = args.Headless ? DisplayMode.Headless : DisplayMode.Clyde;
 
diff --git a/Robust.Server/Program.cs b/Robust.Server/Program.cs
index 811d8c6cac..d711768f5a 100644
--- a/Robust.Server/Program.cs
+++ b/Robust.Server/Program.cs
@@ -48,6 +48,8 @@ namespace Robust.Server
 
         private static void ParsedMain(CommandLineArgs args, bool contentStart, ServerOptions options)
         {
+            ServerWarmup.RunWarmup();
+
             Thread.CurrentThread.Name = "Main Thread";
             var deps = IoCManager.InitThread();
             ServerIoC.RegisterIoC(deps);
diff --git a/Robust.Server/ServerWarmup.cs b/Robust.Server/ServerWarmup.cs
new file mode 100644
index 0000000000..537ee33a74
--- /dev/null
+++ b/Robust.Server/ServerWarmup.cs
@@ -0,0 +1,20 @@
+using System.Threading.Tasks;
+using Robust.Shared;
+
+namespace Robust.Server;
+
+/// <summary>
+/// Logic for "warming up" things like slow static constructors concurrently.
+/// </summary>
+internal static class ServerWarmup
+{
+    public static void RunWarmup()
+    {
+        Task.Run(WarmupCore);
+    }
+
+    private static void WarmupCore()
+    {
+        SharedWarmup.WarmupCore();
+    }
+}
diff --git a/Robust.Shared/Resources/RsiLoading.cs b/Robust.Shared/Resources/RsiLoading.cs
index 86eca2942a..8a9853c7be 100644
--- a/Robust.Shared/Resources/RsiLoading.cs
+++ b/Robust.Shared/Resources/RsiLoading.cs
@@ -96,6 +96,12 @@ internal static class RsiLoading
         return new RsiMetadata(size, states);
     }
 
+    public static void Warmup()
+    {
+        // Just a random RSI I pulled from SS14.
+        const string warmupJson = @"{""version"":1,""license"":""CC-BY-SA-3.0"",""copyright"":""Space Wizards Federation"",""size"":{""x"":32,""y"":32},""states"":[{""name"":""mono""}]}";
+        JsonSerializer.Deserialize<RsiJsonMetadata>(warmupJson, SerializerOptions);
+    }
 
     internal sealed class RsiMetadata
     {
diff --git a/Robust.Shared/SharedWarmup.cs b/Robust.Shared/SharedWarmup.cs
new file mode 100644
index 0000000000..0b6e6ada58
--- /dev/null
+++ b/Robust.Shared/SharedWarmup.cs
@@ -0,0 +1,21 @@
+using System.Runtime.CompilerServices;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Maths;
+
+namespace Robust.Shared;
+
+/// <summary>
+/// Logic for "warming up" things like slow static constructors concurrently.
+/// </summary>
+internal static class SharedWarmup
+{
+    [MethodImpl(MethodImplOptions.NoOptimization)]
+    public static void WarmupCore()
+    {
+        // Color's cctor unironically takes ~12ms.
+        RuntimeHelpers.RunClassConstructor(typeof(Color).TypeHandle);
+
+        // This ends up initializing prometheus-net which takes quite a while.
+        RuntimeHelpers.RunClassConstructor(typeof(EntitySystemManager).TypeHandle);
+    }
+}