vkGetPastPresentationTimingEXT

Because of the asynchronous nature of the presentation engine, the timing information for a given vkQueuePresentKHR command may only becomes available some time after the presentation has occurred. These time values should be asynchronously queried, and are returned if available. All time values are in nanoseconds, according to the time-domain being used.

To asynchronously query the presentation engine for newly-available timing information about one or more previous presents to a given swapchain, call:

VkResult vkGetPastPresentationTimingEXT(
    VkDevice device,
    const VkPastPresentationTimingInfoEXT* pPastPresentationTimingInfo,
    VkPastPresentationTimingPropertiesEXT* pPastPresentationTimingProperties);

pub fn get_past_presentation_timing_ext(
    device: vk::Device,
    p_past_presentation_timing_info: *const vk::PastPresentationTimingInfoEXT,
    p_past_presentation_timing_properties: *mut vk::PastPresentationTimingPropertiesEXT,
) -> vk::Result;

• device is the device associated with swapchain.
• pPastPresentationTimingInfo is a pointer to an instance of the VkPastPresentationTimingInfoEXT structure.
• pPastPresentationTimingProperties is a pointer to an instance of the VkPastPresentationTimingPropertiesEXT structure.

If upon return the value of VkPastPresentationTimingPropertiesEXT::presentationTimingCount is less than the number of available timing records for the given VkPastPresentationTimingInfoEXT::swapchain, VK_INCOMPLETE is returned instead of VK_SUCCESS to indicate that not all the available values were returned.

Upon return, zero or more slots of the swapchain internal timing results queue, equal to the number of entries written to VkPastPresentationTimingPropertiesEXT::pPresentationTimings for which reportComplete is VK_TRUE, are made available for future vkQueuePresentKHR calls. Elements of pPresentationTimings are arranged in ascending order of present ids.

Timing information may become available out of order with regards to their associated vkQueuePresentKHR order. VK_PAST_PRESENTATION_TIMING_ALLOW_OUT_OF_ORDER_RESULTS_BIT_EXT can be set in VkPastPresentationTimingInfoEXT::flags to allow vkGetPastPresentationTimingEXT to return results in that same order. Otherwise, results are returned in the order of their associated vkQueuePresentKHR calls.

There is no requirement for any precise timing relationship between the completion of a present stage and the availability of any associated timing information. However, results must be made available in finite time.

As an exception to the normal rules for objects which are externally synchronized, swapchain may be simultaneously used by other threads in calls to functions other than vkDestroySwapchainKHR and vkCreateSwapchainKHR with swapchain used as an oldSwapchain. Access to the swapchain timing information must be atomic within the implementation.