Bump the thread pool min threads to improve performance (#81)

- We need to bump up the min threads to something reasonable so that the dashboard doesn't take forever
to serve requests. All console IO is blocking in .NET so capturing stdoutput and stderror results in blocking thread pool thread
The thread pool handles bursts poorly and HTTP requests end up getting stuck behind spinning up docker containers and processes.

src/tye/Program.RunCommand.cs

@@ -2,11 +2,13 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System;
 using System.CommandLine;
 using System.CommandLine.Invocation;
 using System.IO;
-using Tye.Hosting;
+using System.Threading;
 using Tye.ConfigModel;
+using Tye.Hosting;
 
 namespace Tye
 {
@@ -62,11 +64,30 @@ namespace Tye
                 }
 
                 var application = ConfigFactory.FromFile(path);
+                var serviceCount = application.Services.Count;
+
+                InitializeThreadPoolSettings(serviceCount);
+
                 var host = new TyeHost(application.ToHostingApplication(), args);
                 return host.RunAsync();
             });
 
             return command;
         }
+
+        private static void InitializeThreadPoolSettings(int serviceCount)
+        {
+            ThreadPool.GetMinThreads(out var workerThreads, out var completionPortThreads);
+
+            // We need to bump up the min threads to something reasonable so that the dashboard doesn't take forever
+            // to serve requests. All console IO is blocking in .NET so capturing stdoutput and stderror results in blocking thread pool threads.
+            // The thread pool handles bursts poorly and HTTP requests end up getting stuck behind spinning up docker containers and processes.
+
+            // Bumping the min threads doesn't mean we'll have min threads to start, it just means don't add a threads very slowly up to
+            // min threads
+            ThreadPool.SetMinThreads(Math.Max(workerThreads, serviceCount * 4), completionPortThreads);
+
+            // We use serviceCount * 4 because we currently launch multiple processes per service, this gives the dashboard some breathing room
+        }
     }
 }