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Unity Engine

Get started with Burst

Read time 2 minutesLast updated 13 days ago
You can use Burst to compile jobs or static methods in non-job C# types. To start using the Burst compiler in your code, decorate a job or static method with the 
[BurstCompile]
 attribute.
For more information on where and when to apply the 
[BurstCompile]
attribute, refer to Marking code for Burst compilation.

Compiling jobs with Burst

For jobs, you only need to apply the 
[BurstCompile]
attribute to the job declaration and Burst compiles everything inside the job automatically. The following example demonstrates this:
using Unity.Burst;using Unity.Collections;using Unity.Jobs;using UnityEngine;public class MyBurst2Behavior : MonoBehaviour{    void Start()    {        var input = new NativeArray<float>(10, Allocator.Persistent);        var output = new NativeArray<float>(1, Allocator.Persistent);        for (int i = 0; i < input.Length; i++)            input[i] = 1.0f * i;        var job = new MyJob        {            Input = input,            Output = output        };        job.Schedule().Complete();        Debug.Log("The result of the sum is: " + output[0]);        input.Dispose();        output.Dispose();    }    // Using BurstCompile to compile a Job with Burst    [BurstCompile]    private struct MyJob : IJob    {        [ReadOnly]        public NativeArray<float> Input;        [WriteOnly]        public NativeArray<float> Output;        public void Execute()        {            float result = 0.0f;            for (int i = 0; i < Input.Length; i++)            {                result += Input[i];            }            Output[0] = result;        }    }}

Compiling static methods with Burst

For static methods, you must apply the 
[BurstCompile]
attribute to both the individual methods you want Burst to compile and to the declaration of the parent type. The following example demonstrates this:
using Unity.Burst;using Unity.Collections;using Unity.Jobs;using UnityEngine;[BurstCompile]public static class MyBurstUtilityClass{    [BurstCompile]    public static void BurstCompiled_MultiplyAdd(in float4 mula, in float4 mulb, in float4 add, out float4 result)    {        result = mula * mulb + add;    }}
For more information on how you can call this Burst-compiled utility class and its member method from your C# code, refer to Calling Burst-compiled code.

Limitations

Burst supports most C# expressions and statements, with a few exceptions. For more information, refer to C# language support.

Compilation

Burst compiles your code just-in-time (JIT) while in Play mode in the Editor, and ahead-of-time (AOT) when your application runs in a Player. For more information on compilation, refer to Burst compilation

Command line options

You can pass the following options to the Unity Editor on the command line to control Burst:
  • --burst-disable-compilation
    disables Burst.
  • --burst-force-sync-compilation
    force Burst to compile synchronously.
For more information, refer to Burst compilation.

Additional resources