using System.Diagnostics;

using UnityEngine;

using Unity.Jobs;

using Unity.Collections;

using Debug = UnityEngine.Debug;

using System.Threading.Tasks;

using Unity.Burst;

​

public class JobsTest : MonoBehaviour

{

    [SerializeField]

    private int _iterations;

​

    private enum Method

    {

        Standard,

        Tasks,

        JobsArray

    }

​

    [SerializeField]

    private Method _method;

​

    private bool _run = false;

​

    private readonly Stopwatch _stopWatch = new Stopwatch();

​

    private NativeArray<JobHandle> _nativeHandles;

    private Task[] _tasks;

​

    private void Update()

    {

        if (!_run)

        {

            _nativeHandles = new NativeArray<JobHandle>(

                          _iterations, Allocator.Temp);

            _tasks = new Task[_iterations];

​

            switch (_method)

            {

                case Method.Standard:

                    {

                        _stopWatch.Start();

                        for (int i = 0; i < _iterations; ++i)

                        {

                            DumbTest();

                        }

                        _stopWatch.Stop();

                        Debug.Log(_method.ToString() + " " + 

                                   _stopWatch.ElapsedMilliseconds + "ms");

                        break;

                    }

                case Method.Tasks:

                    {

                        _stopWatch.Start();

                        for (int i = 0; i < _iterations; ++i)

                        {

                            _tasks[i] = Task.Factory.StartNew(DumbTest);

                        }

                        Task.WaitAll(_tasks);

                        _stopWatch.Stop();

                        Debug.Log(_method.ToString() + " " + 

                                    _stopWatch.ElapsedMilliseconds + "ms");

                        break;

                    }

                case Method.JobsArray:

                    {

                        _stopWatch.Start();

                        for (int i = 0; i < _iterations; ++i)

                        {

                            _nativeHandles[i] = CreateJobHandle();

                        }

                        JobHandle.CompleteAll(_nativeHandles);

                        _stopWatch.Stop();

                        Debug.Log(_method.ToString() + " " + 

                                   _stopWatch.ElapsedMilliseconds + "ms");

                        break;

                    }

            }

        }

        _run = true;

    }

​

    public JobHandle CreateJobHandle()

    {

        var job = new TestJob();

        return job.Schedule();

    }

​

    //[BurstCompile]

    public struct TestJob : IJob

    {

        public void Execute()

        {

            DumbTest();

        }

    }

​

    public static void DumbTest()

    {

        float value = 0f;

        for (int i = 0; i < 60000; ++i)

        {

            value += Mathf.Exp(i) * Mathf.Sqrt(value);

        }

    }

}