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| |
| |
| ## Components |
| |
| ### VulkanDeviceAPI |
| |
| Implements the TVM DeviceAPI interface. Owns the core Vulkan datastructures. Is |
| responsible for initializing the Vulkan instance and devices, querying for |
| possible extensions. |
| |
| ### VulkanThreadEntry |
| |
| Thread-local state for the Vulkan runtime. Maintains a staging buffer (for |
| copies), and a VulkanStream per device. |
| |
| ### VulkanWrappedFunc |
| |
| Responsible for launching computation kernels. Responsible for obtaining a |
| VulkanPipeline instance (from the VulkanModuleNode), and launches the kernel |
| (via immediate or deferred mode) on the active VulkanStream instance. |
| |
| ## Stream execution in the Vulkan programming model. |
| |
| The natural model for TVM DeviceAPI implementation and runtime follows the CUDA |
| API model. That is, we launch "kernels" onto a (implicit or explicit) "stream" |
| (which execute asynchronously with respect to the host, but ordered with respect |
| to the stream), and explicitly synchronize the stream with respect to the host. |
| We simulate this behaviour in the Vulkan model by maintaining a thread-local |
| `vkCommandBuffer` instance, and queueing up (or eagerly executing, depending on |
| the availability of the `VK_KHR_push_descriptor` extension). When we synchronize |
| the stream, we end the command buffer recording, submit it to the device queue, |
| and wait on the corresponding fence. |
