Signal for an NvSciSyncFence

VkFence (CPU only)

Use the vkQueueSubmit API to submit jobs enqueued on the Vulkan SC queue by providing a valid VkFence to fence as a parameter. The fence tracks the completion of all the jobs submitted to the Vulkan SC queue on which the API was invoked.

Use vkGetFenceSciSyncFenceNV to get the pending NvSciSyncFence. The application must provide a valid VkFence to VkFenceGetSciSyncInfoNV::fence from which the NvSciSyncFence is extracted.

Waiting on this NvSciSyncFence is equivalent to waiting for the completion of all prior submissions on the queue, in submission order. Once all the submissions have completed, the NvSciSyncFence is signaled and all the potential waiters on this NvSciSyncFence are unblocked. This signal occurs asynchronously on the GPU.

VkSemaphore

• GPU Signal

Use the vkQueueSubmit API to submit jobs enqueued on the Vulkan SC queue. This API takes VkSubmitInfo::pSignalSemaphores as a parameter. In addition, application must chain a valid VkTimelineSemaphoreSubmitInfo struct to the VkSubmitInfo::pNext, where VkTimelineSemaphoreSubmitInfo::pSignalSemaphoreValues should be tracked and maintained by application (The initial value is always 0).

As applications must maintain the signal value by incrementing it for each submission, use the NvSciSync API NvSciSyncFenceUpdateFence to get the pending NvSciSyncFence, where the id is always 0 because VkSemaphore only supports one sysmem semaphore as a signaler. This NvSciSyncFence tracks prior batches to the queue, in signal operation order. Once it is signaled, all the potential waiters on this NvSciSyncFence will be unblocked. This signal occurs asynchronously on the GPU.

• CPU Signal

Use the vkSignalSemaphore API to signal on the CPU. This API takes a validVkSemaphoreSignalInfo::semaphore as a parameter. In addition, applications must track and maintain the signal value and provide it as a parameter to VkSemaphoreSignalInfo::value.

Use the NvSciSync API NvSciSyncFenceUpdateFence to get the pending NvSciSyncFence. The signal occurs asynchronously on the GPU. Once it is signaled, all the potential waiters on this NvSciSyncFence will be unblocked.

• Deterministic Fence

Vulkan SC supports Deterministic Fence in VkSemaphore. When Deterministic Fence is enabled in NvSciSync, Vulkan SC signaler doesn’t need to export NvSciSyncFence to NvSciIPC. When Vulkan SC applications pass a counter value to signal a VkSemaphore, applications pass the value, which increments by +1 (exactly one), from the counter value of the previous semaphore signal operation on that VkSemaphore, in signal operation order. The initial counter value is 0.