Skip to content

README.adoc

Latest commit

 

History

History
82 lines (67 loc) · 5.06 KB

README.adoc

File metadata and controls

82 lines (67 loc) · 5.06 KB

Pipeline binary (VK_KHR_pipeline_binary)

Overview

VK_KHR_pipeline_binary lets you explicitly capture and reuse driver-produced pipeline binaries. Instead of relying only on opaque pipeline caches, you can:

  • Compute a portable pipeline key up front for a given set of creation parameters.

  • Ask the driver to give you an implementation-specific binary for that key.

  • Persist that binary and reuse it on the same driver/device to avoid runtime compilation hitches.

This sample builds a tiny compute pipeline solely to demonstrate that flow. It logs support, queries a key, and (if available) captures the binary data.

Why and when to use it

Pipeline caches are useful, but they are intentionally opaque and not keyed by a structure you can compute deterministically. Pipeline binaries add:

  • Deterministic cache management (you can compute the key before creating a pipeline).

  • Cross-process or install-time pre-warming strategies.

  • A clear, explicit handle (VkPipelineBinaryKHR) you can store and manage.

They complement other techniques:

  • VK_EXT_graphics_pipeline_library reduces link-time work, but doesn’t hand you the final binary for persistence.

  • VK_EXT_shader_object changes the binding model, not binary persistence.

How it works (TL;DR)

  1. Prepare the same creation info you’d pass to vkCreate*Pipelines (compute or graphics).

  2. Wrap it in VkPipelineCreateInfoKHR.

  3. vkGetPipelineKeyKHR(device, &VkPipelineCreateInfoKHR, &VkPipelineBinaryKeyKHR) → portable key.

  4. vkCreatePipelineBinariesKHR(device, &VkPipelineBinaryCreateInfoKHR, …) → VkPipelineBinaryKHR handle.

  5. vkGetPipelineBinaryDataKHR(device, &VkPipelineBinaryDataInfoKHR, …) → query size, then fetch bytes.

  6. Store bytes together with device/vendor/driver identifiers and the key.

Required Vulkan extensions and features

To use feature chaining like the other samples, this sample enables the following and requests the needed feature explicitly:

  • Instance: VK_KHR_get_physical_device_properties2 — required by the framework to chain extension feature structs during device creation.

  • Device: VK_KHR_pipeline_binary — the extension demonstrated here.

  • Device: VK_KHR_maintenance5 — defines the VkPipelineCreateFlags2 flag space that includes CAPTURE_DATA (not required for this sample’s path, but commonly expected by validation).

  • Device: VK_KHR_dynamic_rendering, VK_KHR_depth_stencil_resolve, VK_KHR_create_renderpass2 — commonly used by the framework/WSI paths; enabled to avoid spurious present-time validation issues.

Note: This sample uses the pPipelineCreateInfo path when creating pipeline binaries, so it does not require creating a live pipeline with CAPTURE_DATA set.

Walkthrough of the code

  • log_pipeline_binary_support() uses vkGetPhysicalDeviceFeatures2/properties2 to show what the driver supports and prefers regarding internal caches and compression.

  • demo_pipeline_key_and_binary():

    • Reuses the cached compute pipeline creation info and wraps it in VkPipelineCreateInfoKHR.

    • Calls vkGetPipelineKeyKHR to compute the key.

    • Calls vkCreatePipelineBinariesKHR with pPipelineCreateInfo set (and pipeline/pKeysAndDataInfo null) to get a VkPipelineBinaryKHR.

    • Calls vkGetPipelineBinaryDataKHR twice to first query size, then fetch bytes (requires a valid VkPipelineBinaryKeyKHR pointer on both calls).

Best practices and caveats

  • Treat captured binaries as opaque and device/driver-specific; don’t assume portability across vendors or driver revisions.

  • Record identity metadata (vendor ID, device ID, driver version, pipeline key) so you can invalidate stale entries.

  • Some drivers may prefer or enforce internal caches; honor properties like pipelineBinaryPrefersInternalCache.

  • Not all implementations will return data; some may return zero bytes. Handle that gracefully.

  • Any change in creation parameters changes the key and the resulting binary.

References