isystem-burst-compile

To eliminate managed dispatch overhead in Unity ECS, implement systems as unmanaged ISystem structs with Burst-compiled entry points. This ensures high-frequency simulation logic uses only unmanaged components and avoids managed Unity APIs.

Make Unity DOTS ISystem structs Burst-compatible by using Burst-safe fields, accessing ECS queries through ref SystemState, and applying SystemAPI.Query patterns while avoiding managed types like string, List<T>, or MonoBehaviour references.

Use ISystem for Unity ECS performance when writing high-frequency simulation logic such as movement, physics-style updates, or gameplay state stepping that doesn't require managed types or managed Unity APIs.

Managed types like string, List<T>, MonoBehaviour references, and managed Unity APIs prevent Burst compilation in ECS systems. Accessing these managed component patterns breaks Burst-safe execution paths and reverts to managed dispatch overhead.

Yes, you can use BurstCompile on all ISystem lifecycle methods in Unity DOTS. Mark OnCreate, OnUpdate, and OnDestroy with BurstCompile to compile the hot paths and ensure native code generation for unmanaged ECS simulation systems.

Burst-compiled ISystem structs in Unity ECS are limited to unmanaged, managed-free components and cannot use managed Unity APIs. Every field, call, and ECS query must remain Burst-safe, restricting use to native simulation logic without managed type access.