barrier(afterQueueStages:beforeStages:visibilityOptions:)

Declaration

func barrier(afterQueueStages: MTLStages, beforeStages: MTLStages, visibilityOptions: MTL4VisibilityOptions = [ .device ])

Parameters

• afterQueueStages:

  Mtlstages mask that represents the stages of work to wait for. This argument applies to work corresponding to these stages you encode in prior command encoders, and not for the current encoder.

• beforeStages:

  Mtlstages mask that represents the stages of work that wait. This argument applies to work you encode in the current command encoder.

• visibilityOptions:

  Mtl4visibilityoptions of the barrier.

Mentioned in

• Synchronizing passes with consumer barriers
• Synchronizing stages within a pass

Discussion

Encode a barrier that guarantees that any subsequent work you encode in the current command encoder that corresponds to the beforeStages stages doesn’t proceed until Metal completes all work prior to the current command encoder corresponding to the afterQueueStages stages, completes.

Metal can reorder the exact point where it applies the barrier, so encode the barrier as close to the command that consumes the resource as possible. Don’t use this method for synchronizing resource access within the same pass.

If you need to synchronize work within a pass that you encode with an instance of a subclass of MTLCommandEncoder, use memory barriers instead. For subclasses of MTL4CommandEncoder, use encoder barriers.

You can specify afterQueueStages and beforeStages that contain MTLStages unrelated to the current command encoder.