memory monitoring

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;

namespace TotalMemory
{
    public class Program
    {
        private static readonly Func<long> getAllocatedBytesForCurrentThread = GetAllocatedBytesForCurrentThread();

        public static void Main(string[] args)
        {
            TestMonitoringTotalAllocatedMemorySize();
        }

        public static void TestMonitoringTotalAllocatedMemorySize()
        {
#if CLASSIC
            AppDomain.MonitoringIsEnabled = true;
#endif

            var temp = new HashSet<string>();
            temp.Add("provoke JIT, static ctors etc");
            if(temp.Count != 1)
                Environment.FailFast("Impossible");

            var countersToUse = new [] {1, 5, 10, 25, 50, 100, 250, 500, 1000, 2500, 5000, 10000, 100000, 250000, 500000};
            foreach (var counter in countersToUse)
            {
                var hashSetBefore = GetMemory();

                var loopCounter = 0;
                for (int i = 0; i < counter; i++)
                {
                    var test = new HashSet<string>();
                    loopCounter += test.Count;
                }

                var hashSetAfter = GetMemory();
                var totalAlloc = hashSetAfter - hashSetBefore;
                Console.WriteLine(
                    "HashSet<string>() = {0,8:N2} bytes (Total = {1,12:N0} bytes, Counter = {2,8:N0}), Current = {3,8:N0} bytes",
                    (double)totalAlloc / counter, totalAlloc, counter, GC.GetTotalMemory(forceFullCollection: true));
            }
        }

        static long GetMemory()
        {
            GC.Collect();
#if CLASSIC
            return AppDomain.CurrentDomain.MonitoringTotalAllocatedMemorySize;
#else
            return getAllocatedBytesForCurrentThread();
#endif
        }

        static Func<long> GetAllocatedBytesForCurrentThread()
        {
            // for some versions of .NET Core this method is internal, 
            // for some public and for others public and exposed ;)
            var method = typeof(GC).GetTypeInfo().GetMethod("GetAllocatedBytesForCurrentThread",
                            BindingFlags.Public | BindingFlags.Static)
                      ?? typeof(GC).GetTypeInfo().GetMethod("GetAllocatedBytesForCurrentThread",
                            BindingFlags.NonPublic | BindingFlags.Static);

            return () => (long)method.Invoke(null, null);
        }
    }
}

project.json

{
  "version": "1.0.0-*",
  "buildOptions": {
    "emitEntryPoint": true
  },

  "runtimeOptions": {
    "configProperties": {
      "System.GC.Server": false,
      "System.GC.Concurrent": true
    }
  },

  "frameworks": {
    "net45": {
      "buildOptions": {
        "define": [ "CLASSIC" ]
      },
      "frameworkAssemblies": {
        "System.Reflection": "4.0.0.0"
      }
    },
    "netcoreapp1.1": {
      "buildOptions": {
        "define": [ "CORE" ]
      },
      "dependencies": {
        "Microsoft.NETCore.App": {
          "type": "platform",
          "version": "1.1.0"
        }
      }
    }
  }
}