Get started

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.