Memory Export#

Warning

Experimental features:

  • May be replaced, updated, or removed at any time.

  • Do not require maintaining API/ABI stability of their own additions over time.

  • Do not require conformance testing of their own additions.

Motivation#

The DPC++ Memory Export extension provides new APIs for allocating and deallocating exportable device memory, and obtaining a handle to that memory which can be used in external APIs. This is useful when applications want to share device memory between different APIs.

Without the ability to allocate exportable memory and obtain an interoperable handle, applications have to copy device memory allocated by one API to the host, then copy that host memory back to the device in a memory region allocated by a second API. If the second API modifies that memory, then this process would have to be repeated in the opposite direction in order for the first API to see the changes made to that memory.

This extension enables copy-free sharing of SYCL allocated device memory with external APIs.

Overview#

In this document, we propose the following experimental additions to the Unified Runtime:

  • Exporting Memory

    • Allocating an exportable device resident memory region.

    • Obtaining a handle to the allocated exportable memory region, for the purpose of using this handle to import the memory in external APIs such as Vulkan or DirectX.

    • Freeing the exportable device resident memory region.

Please note that the following enums and types used by this extension are dependent on the Bindless Images extension. Their definitions are provided in exp-bindless-images.yml.

Changelog#

Revision

Changes

1.0

Initial draft with Level Zero adapter implementation

Contributors#