VK_NV_external_memory

Other Extension Metadata

Last Modified Date

2016-08-19

IP Status

No known IP claims.

Contributors

• James Jones, NVIDIA
• Carsten Rohde, NVIDIA

Description

Applications may wish to export memory to other Vulkan instances or other APIs, or import memory from other Vulkan instances or other APIs to enable Vulkan workloads to be split up across application module, process, or API boundaries. This extension enables applications to create exportable Vulkan memory objects such that the underlying resources can be referenced outside the Vulkan instance that created them.

New Structures

• Extending VkImageCreateInfo:
  • VkExternalMemoryImageCreateInfoNV
• Extending VkMemoryAllocateInfo:
  • VkExportMemoryAllocateInfoNV

New Enum Constants

• VK_NV_EXTERNAL_MEMORY_EXTENSION_NAME
• VK_NV_EXTERNAL_MEMORY_SPEC_VERSION
• Extending VkStructureType:
  • VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV
  • VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV

Issues

1) If memory objects are shared between processes and APIs, is this considered aliasing according to the rules outlined in the Memory Aliasing section?

RESOLVED: Yes, but strict exceptions to the rules are added to allow some forms of aliasing in these cases. Further, other extensions may build upon these new aliasing rules to define specific support usage within Vulkan for imported native memory objects, or memory objects from other APIs.

2) Are new image layouts or metadata required to specify image layouts and layout transitions compatible with non-Vulkan APIs, or with other instances of the same Vulkan driver?

RESOLVED: No. Separate instances of the same Vulkan driver running on the same GPU should have identical internal layout semantics, so applications have the tools they need to ensure views of images are consistent between the two instances. Other APIs will fall into two categories: Those that are Vulkan compatible (a term to be defined by subsequent interopability extensions), or Vulkan incompatible. When sharing images with Vulkan incompatible APIs, the Vulkan image must be transitioned to the VK_IMAGE_LAYOUT_GENERAL layout before handing it off to the external API.

Note this does not attempt to address cross-device transitions, nor transitions to engines on the same device which are not visible within the Vulkan API. Both of these are beyond the scope of this extension.

Examples

    // TODO: Write some sample code here.

Version History

• Revision 1, 2016-08-19 (James Jones)
  • Initial draft