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Coroutines and the Unity C# Job System?

Discussion in 'C# Job System' started by neounix, Jun 24, 2018.

  1. neounix


    Jan 9, 2017

    Sorry for being so ignorant (and frustrated) about this; but I really want to take advantage of multi-core computing by using my existing thousands of lines of Unity MonoBehaviour code.

    Is it possible to use the Unity C# Job system to simply submit / direct a Coroutine() to run on it's on thread in a multi-core machine to Instantiate() MonoBehaviour game objects?

    Also, similar question for Unity Coroutines in general? Can we simply use the Unity C# job system to submit any general Coroutine() to be executed on different cores in a multi-core device?

    Maybe it better I forget about Unity Jobs and ECS and just use the C# native:

    Code (CSharp):
    1. using System.Threading;
    Last edited: Jun 24, 2018
  2. recursive


    Jul 12, 2012
    Unfortunately, in order to take advantage of the new jobs system, you'll have to rewrite the data you send to the jobs so that only blittable data types are passed to the job and NativeContainers. The Job system is completely divorced from the coroutine system. You cannot access reference types nor safely call most static functions if they access the normal Unity APIs on a Job, the limited subset is what enables the heavy optimizations.

    Even if you were to use System.Threading, most Unity object types and APIs are not thread-safe regardless, so you'd still need to restructure how you're setting up your data, usually by creating a copy (or reusing a buffer) of what needs to be processed, hand it over to threading land, and only read it back on the main thread after the worker notifies completion or pushes stuff into a shared queue (works but very inefficient).

    If you still want a thread-able API that's closer to what you may have dealt with in coroutines, that allows you to wrap or replace them, you may want to look into the UniRx framework as it has some nice utilities to deal with corutines and it's easy to thread logic and manipulate reference types on a thread. It's still not safe to access Unity's APIs or access most Unity Objects while running thread logic but it's miles away better than dealing with low-level System.Thread(s) and managing communication queues yourself. It's has tools to have logic that runs on a thread, then swaps to a coroutine or vice versa.
    mandisaw and neounix like this.
  3. unityPashok


    Sep 1, 2020
    How to use UniRx with Job System? I tried to implement it but got some errors
    Code (CSharp):
    1. [BurstCompile]
    2.     struct TestJob : IJob
    3.     {
    4.         public void Execute()
    5.         {
    6.             Debug.Log("Hello world");
    8.             Observable.Start(() =>
    9.             {
    10.                 System.Threading.Thread.Sleep(TimeSpan.FromSeconds(1));
    11.                 Debug.Log("end");
    12.             });
    13.         }
    14.     }
  4. recursive


    Jul 12, 2012
    You can't. Everything in UniRx uses managed components and regular .NET threading. This is incompatible with the Unity Job system.