VK_NV_external_sci_sync

{generated}/meta/{refprefix}VK_NV_external_sci_sync.adoc

Other Extension Metadata

Last Modified Date

2022-04-12

Contributors

• Kai Zhang, NVIDIA
• Jeff Bolz, NVIDIA
• Jonathan McCaffrey, NVIDIA
• Daniel Koch, NVIDIA

Description

An application using external memory may wish to synchronize access to that memory using semaphores and fences. This extension enables an application to import and export semaphore and fence payloads to and from NvSciSync objects. To import a NvSciSyncObj to a VkSemaphore or VkFence, applications need to:

• Create an unreconciled NvSciSyncAttrList via NvSciSyncAttrListCreate()
• Fill the private attribute list via vkGetPhysicalDeviceSciSyncAttributesNV()
• Fill the public attribute list via NvSciSyncAttrListSetAttrs()
• Reconcile the NvSciSyncAttrList via NvSciSyncAttrListReconcile()
• Create a NvSciSyncObj via NvSciSyncObjAlloc()
• Import the NvSciSyncObj to a VkSemaphore by passing the VkImportSemaphoreSciSyncInfoNV structure to the vkImportSemaphoreSciSyncObjNV command, or to a VkFence by passing the VkImportFenceSciSyncInfoNV structure to the vkImportFenceSciSyncObjNV command.

To import/export a NvSciSyncFence to a VkFence object, that VkFence object must already have a NvSciSyncObj previously imported.

For details of the NvSciSync APIs and data structures, see the NvStreams Documentation.

Issues

1) What should we call this extension?

RESOLVED. The external API is NvSciSync, but the Vulkan convention is to append the vendor suffix at the end of an identifier. Using NvSciSyncNV seems awkward, so we have chosen to use just the SciSync portion of the name in Vulkan commands and tokens. Since this is for interacting with objects from outside Vulkan, we use "external" in the name, similar to VK_KHR_external_fence_fd. To avoid an explosion of extensions, we include the capability to import and export both semaphores and fences in one extension but include separate features in case implementations only implement (or safety certify) a subset.

2) How do we resolve the NvStreams terminology of NvSciSyncFence which conflicts with the Vulkan SC terminology of VkFence.

RESOLVED: "fence" refers to VkFence. "NvSciSyncFence" refers to the NvStreams type and "VkFence" refers to the Vulkan SC type.

Version History

• Revision 2, 2022-03-29 (Daniel Koch)
  • use separate commands for NvSciSyncFence and NvSciSyncObj handles
• Revision 1, 2020-11-25 (Kai Zhang, Daniel Koch)
  • Initial revision