Optional configurable thread settings (#7870)

* threading settings.

* Proper source name

Author: agr

src/AccountDeleter/Configuration/GalleryConfiguration.cs

@@ -108,5 +108,9 @@ public string SiteRoot
         public bool SelfServiceAccountDeleteEnabled { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
         public string DeploymentLabel { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
         public string UsabillaFeedbackButtonId { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
+        public int? MinWorkerThreads { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
+        public int? MaxWorkerThreads { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
+        public int? MinIoThreads { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
+        public int? MaxIoThreads { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
     }
 }

src/NuGetGallery.Services/Configuration/AppConfiguration.cs

@@ -404,5 +404,14 @@ public string ExternalBrandingMessage
         public string DeploymentLabel { get; set; }
 
         public string UsabillaFeedbackButtonId { get; set; }
+
+        [DefaultValue(null)]
+        public int? MinWorkerThreads { get; set; }
+        [DefaultValue(null)]
+        public int? MaxWorkerThreads { get; set; }
+        [DefaultValue(null)]
+        public int? MinIoThreads { get; set; }
+        [DefaultValue(null)]
+        public int? MaxIoThreads { get; set; }
     }
 }

src/NuGetGallery.Services/Configuration/IAppConfiguration.cs

@@ -455,5 +455,41 @@ public interface IAppConfiguration : IMessageServiceConfiguration
         /// in your button's JavaScript code. Look for "//w.usabilla.com/{button ID}.js".
         /// </summary>
         string UsabillaFeedbackButtonId { get; set; }
+
+        /// <summary>
+        /// Allows to override the default (or externally configured) minWorkerThreads setting. Must be specified with <see cref="MinIoThreads"/>.
+        /// This is a global (not per CPU core) limit.
+        /// See more: 
+        /// https://docs.microsoft.com/en-us/dotnet/api/system.threading.threadpool.setminthreads?view=netframework-4.7.2
+        /// https://docs.microsoft.com/en-us/previous-versions/dotnet/netframework-4.0/7w2sway1(v=vs.100)?redirectedfrom=MSDN
+        /// </summary>
+        int? MinWorkerThreads { get; set; }
+
+        /// <summary>
+        /// Allows to override the default (or externally configured) maxWorkerThreads setting. Must be specified with <see cref="MaxIoThreads"/>
+        /// This is a global (not per CPU core) limit.
+        /// See more: 
+        /// https://docs.microsoft.com/en-us/dotnet/api/system.threading.threadpool.setmaxthreads?view=netframework-4.7.2
+        /// https://docs.microsoft.com/en-us/previous-versions/dotnet/netframework-4.0/7w2sway1(v=vs.100)?redirectedfrom=MSDN
+        /// </summary>
+        int? MaxWorkerThreads { get; set; }
+
+        /// <summary>
+        /// Allows to override the default (or externally configured) minIoThreads setting. Must be specified with <see cref="MinWorkerThreads"/>.
+        /// This is a global (not per CPU core) limit.
+        /// See more: 
+        /// https://docs.microsoft.com/en-us/dotnet/api/system.threading.threadpool.setminthreads?view=netframework-4.7.2
+        /// https://docs.microsoft.com/en-us/previous-versions/dotnet/netframework-4.0/7w2sway1(v=vs.100)?redirectedfrom=MSDN
+        /// </summary>
+        int? MinIoThreads { get; set; }
+
+        /// <summary>
+        /// Allows to override the default (or externally configured) maxIoThreads setting. Must be specified with <see cref="MaxWorkerThreads"/>.
+        /// This is a global (not per CPU core) limit.
+        /// See more: 
+        /// https://docs.microsoft.com/en-us/dotnet/api/system.threading.threadpool.setmaxthreads?view=netframework-4.7.2
+        /// https://docs.microsoft.com/en-us/previous-versions/dotnet/netframework-4.0/7w2sway1(v=vs.100)?redirectedfrom=MSDN
+        /// </summary>
+        int? MaxIoThreads { get; set; }
     }
 }

src/NuGetGallery/App_Start/OwinStartup.cs

@@ -5,12 +5,14 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Net;
+using System.Threading;
 using System.Threading.Tasks;
 using System.Web;
 using System.Web.Hosting;
 using System.Web.Http;
 using System.Web.Mvc;
 using Elmah;
+using Microsoft.Extensions.Logging;
 using Microsoft.Owin;
 using Microsoft.Owin.Logging;
 using Microsoft.Owin.Security;
@@ -20,9 +22,12 @@
 using NuGetGallery.Authentication.Providers;
 using NuGetGallery.Authentication.Providers.Cookie;
 using NuGetGallery.Configuration;
+using NuGetGallery.Diagnostics;
 using NuGetGallery.Infrastructure;
 using Owin;
 
+using ILoggerFactory = Microsoft.Extensions.Logging.ILoggerFactory;
+
 [assembly: OwinStartup(typeof(NuGetGallery.OwinStartup))]
 
 namespace NuGetGallery
@@ -91,6 +96,24 @@ public static void Configuration(IAppBuilder app)
                 }
             }
 
+            var tds = new TraceDiagnosticsSource(nameof(OwinStartup), dependencyResolver.GetService<ITelemetryClient>());
+            if (config.Current.MaxWorkerThreads.HasValue && config.Current.MaxIoThreads.HasValue)
+            {
+                int defaultMaxWorkerThreads, defaultMaxIoThreads;
+                ThreadPool.GetMaxThreads(out defaultMaxWorkerThreads, out defaultMaxIoThreads);
+                tds.Information($"Default maxWorkerThreads: {defaultMaxWorkerThreads}, maxIoThreads: {defaultMaxIoThreads}");
+                var success = ThreadPool.SetMaxThreads(config.Current.MaxWorkerThreads.Value, config.Current.MaxIoThreads.Value);
+                tds.Information($"Attempt to update max threads to {config.Current.MaxWorkerThreads.Value}, {config.Current.MaxIoThreads.Value}, success: {success}");
+            }
+            if (config.Current.MinWorkerThreads.HasValue && config.Current.MinIoThreads.HasValue)
+            {
+                int defaultMinWorkerThreads, defaultMinIoThreads;
+                ThreadPool.GetMinThreads(out defaultMinWorkerThreads, out defaultMinIoThreads);
+                tds.Information($"Default minWorkerThreads: {defaultMinWorkerThreads}, minIoThreads: {defaultMinIoThreads}");
+                var success = ThreadPool.SetMinThreads(config.Current.MinWorkerThreads.Value, config.Current.MinIoThreads.Value);
+                tds.Information($"Attempt to update min threads to {config.Current.MinWorkerThreads.Value}, {config.Current.MinIoThreads.Value}, success: {success}");
+            }
+
             // Get the local user auth provider, if present and attach it first
             Authenticator localUserAuthenticator;
             if (auth.Authenticators.TryGetValue(Authenticator.GetName(typeof(LocalUserAuthenticator)), out localUserAuthenticator))