Benefits of vkCmdDrawIndirect in MoltenVK?

[WalkerWhite]

The benefit of indirect draw in Vulkan is that it is supposed to batch up draw calls which are looped through on the GPU. But looking at the code for MoltenVK it seems that vkCmdDrawIndirect and vkCmdDrawIndexedIndirect do a CPU loop through the draw calls. When I do a capture frame in Xcode, I see commands that are identical to if I had called vkCmdDraw or vkCmdDrawIndexed in a tight loop myself. In addition, the code for the indirect calls in MoltenVK seem to have a lot of potential buffer copies.

With that in mind, are there any benefits to using indirect drawing in MoltenVK?

[billhollings]

Unfortunately, Metal does not currently have a draw call that supports the drawCount parameter being passed to the GPU, so MoltenVK has to handle that part with the CPU in the driver (and yes, as if you'd executed a loop yourself).