Request for IJobChunk.ScheduleSingle

Unity Engine
,
1

Similar to IJobProcessComponentData.ScheduleSingle, can we also get a schedule function which runs single-threaded for IJobChunk?

4 Likes
2

IJobChunk is run single threaded. If you pass down the job handle, you can tell other IJobChunk to wait for the previous one.

for(i = 0; i > length; i++){
     var job = new IJobChunk(); // Create Job
     inputdeps = job.schedule(this, inputdeps); // Tell this job to wait for previous job in previous loop
}

I’m not tested yet but I think relatively job handle should work like that.

3

IJobChunk runs as a parallel-for job. If you look into the source (IJobChunk.cs) you’ll see this line

return JobsUtility.ScheduleParallelFor(ref scheduleParams, totalChunks, 1);

A ScheduleSingle extension method would call JobsUtility.Schedule instead of ScheduleParallelFor.

4

Yeah that’s not true. Chunks are spread across threads.

5

Well my bad. That is badly written and I do not have that deep understand of ECS.

1 Like
6

Sorry didn’t mean to come off so blunt.

From memory, every job except IJob is parallel by default.

1 Like
7

bump

8

Since it might be a while for us to get this, I wrote a quick’n’dirty work-around

public static JobHandle ScheduleSingle<T>(this T job, EntityQuery query, JobHandle dependsOn)
    where T : struct, IJobChunk {
  var chunks = query.CreateArchetypeChunkArray(Allocator.TempJob, out JobHandle chunksHandle);
  dependsOn = JobHandle.CombineDependencies(dependsOn, chunksHandle);
  return new JobChunkSingleRunner<T> {
    RealJob = job,
    Chunks = chunks,
  }.Schedule(dependsOn);
}

[BurstCompile]
struct JobChunkSingleRunner<T> : IJob where T : IJobChunk {
  public T RealJob;
  [DeallocateOnJobCompletion]
  public NativeArray<ArchetypeChunk> Chunks;

  public void Execute() {
    int firstEntityIndex = 0;
    for (int i = 0; i < Chunks.Length; ++i) {
      RealJob.Execute(Chunks[i], i, firstEntityIndex);
      firstEntityIndex += Chunks[i].Count;
    }
  }
}
1 Like
9

please add this.