Burst compilation in Play mode
When you create a build of your project, Burst compiles all the supported code ahead-of-time (AOT) into a native library which Unity ships with your application.
When previewing your application in the Editor's Play mode, Burst provides the following compilation modes:
- Asynchronous: Parts of your code marked for Burst compilation can run as managed, just-in-time (JIT) compiled code in the .NET runtime while waiting for Burst compilation to complete. This is the default behavior.
- Synchronous: Parts of your code marked for Burst compilation can only run as Burst-compiled native code and your application must wait for Burst compilation to complete.
Synchronous compilation
To force synchronous compilation in Play mode, set the CompileSynchronously property to true as follows:
[BurstCompile(CompileSynchronously = true)]
public struct MyJob : IJob
{
// ...
}
Waiting for synchronous compilation affects the current running frame, which can cause hitches and make your application unresponsive. Synchronous compilation is only recommended in the following situations:
- If you have a long running job that only runs once. The performance of the compiled code might outweigh the downsides of synchronous compilation.
- If you're profiling a Burst job and want to test the code from the Burst compiler. When you do this, perform a warmup to discard any timing measurements from the first call to the job. This is because the profiling data includes the compilation time and skews the result.
- To aid with debugging the difference between managed and Burst compiled code.