Class EXTCalibratedTimestamps


  • public class EXTCalibratedTimestamps
    extends java.lang.Object
    This extension provides an interface to query calibrated timestamps obtained quasi simultaneously from two time domains.
    Name String
    VK_EXT_calibrated_timestamps
    Extension Type
    Device extension
    Registered Extension Number
    185
    Revision
    1
    Extension and Version Dependencies
    • Requires Vulkan 1.0
    Contact
    Last Modified Date
    2018-10-04
    IP Status
    No known IP claims.
    Contributors
    • Matthaeus G. Chajdas, AMD
    • Alan Harrison, AMD
    • Derrick Owens, AMD
    • Daniel Rakos, AMD
    • Jason Ekstrand, Intel
    • Keith Packard, Valve
    • Method Detail

      • nvkGetPhysicalDeviceCalibrateableTimeDomainsEXT

        public static int nvkGetPhysicalDeviceCalibrateableTimeDomainsEXT​(VkPhysicalDevice physicalDevice,
                                                                          long pTimeDomainCount,
                                                                          long pTimeDomains)
        Parameters:
        pTimeDomainCount - a pointer to an integer related to the number of calibrateable time domains available or queried, as described below.
      • vkGetPhysicalDeviceCalibrateableTimeDomainsEXT

        public static int vkGetPhysicalDeviceCalibrateableTimeDomainsEXT​(VkPhysicalDevice physicalDevice,
                                                                         java.nio.IntBuffer pTimeDomainCount,
                                                                         @Nullable
                                                                         java.nio.IntBuffer pTimeDomains)
        Query calibrateable time domains.
        C Specification

        To query the set of time domains for which a physical device supports timestamp calibration, call:

        
         VkResult vkGetPhysicalDeviceCalibrateableTimeDomainsEXT(
             VkPhysicalDevice                            physicalDevice,
             uint32_t*                                   pTimeDomainCount,
             VkTimeDomainEXT*                            pTimeDomains);
        Description

        If pTimeDomains is NULL, then the number of calibrateable time domains supported for the given physicalDevice is returned in pTimeDomainCount. Otherwise, pTimeDomainCount must point to a variable set by the user to the number of elements in the pTimeDomains array, and on return the variable is overwritten with the number of values actually written to pTimeDomains. If the value of pTimeDomainCount is less than the number of calibrateable time domains supported, at most pTimeDomainCount values will be written to pTimeDomains. If pTimeDomainCount is smaller than the number of calibrateable time domains supported for the given physicalDevice, INCOMPLETE will be returned instead of SUCCESS to indicate that not all the available values were returned.

        Valid Usage (Implicit)
        • physicalDevice must be a valid VkPhysicalDevice handle
        • pTimeDomainCount must be a valid pointer to a uint32_t value
        • If the value referenced by pTimeDomainCount is not 0, and pTimeDomains is not NULL, pTimeDomains must be a valid pointer to an array of pTimeDomainCount VkTimeDomainEXT values
        Return Codes
        On success, this command returns
        On failure, this command returns
        Parameters:
        physicalDevice - the physical device from which to query the set of calibrateable time domains.
        pTimeDomainCount - a pointer to an integer related to the number of calibrateable time domains available or queried, as described below.
        pTimeDomains - either NULL or a pointer to an array of VkTimeDomainEXT values, indicating the supported calibrateable time domains.
      • nvkGetCalibratedTimestampsEXT

        public static int nvkGetCalibratedTimestampsEXT​(VkDevice device,
                                                        int timestampCount,
                                                        long pTimestampInfos,
                                                        long pTimestamps,
                                                        long pMaxDeviation)
        Unsafe version of: GetCalibratedTimestampsEXT
        Parameters:
        timestampCount - the number of timestamps to query.
      • vkGetCalibratedTimestampsEXT

        public static int vkGetCalibratedTimestampsEXT​(VkDevice device,
                                                       VkCalibratedTimestampInfoEXT.Buffer pTimestampInfos,
                                                       java.nio.LongBuffer pTimestamps,
                                                       java.nio.LongBuffer pMaxDeviation)
        Query calibrated timestamps.
        C Specification

        In order to be able to correlate the time a particular operation took place at on timelines of different time domains (e.g. a device operation vs a host operation), Vulkan allows querying calibrated timestamps from multiple time domains.

        To query calibrated timestamps from a set of time domains, call:

        
         VkResult vkGetCalibratedTimestampsEXT(
             VkDevice                                    device,
             uint32_t                                    timestampCount,
             const VkCalibratedTimestampInfoEXT*         pTimestampInfos,
             uint64_t*                                   pTimestamps,
             uint64_t*                                   pMaxDeviation);
        Description
        Note

        The maximum deviation may vary between calls to vkGetCalibratedTimestampsEXT even for the same set of time domains due to implementation and platform specific reasons. It is the application's responsibility to assess whether the returned maximum deviation makes the timestamp values suitable for any particular purpose and can choose to re-issue the timestamp calibration call pursuing a lower devation value.

        Calibrated timestamp values can be extrapolated to estimate future coinciding timestamp values, however, depending on the nature of the time domains and other properties of the platform extrapolating values over a sufficiently long period of time may no longer be accurate enough to fit any particular purpose so applications are expected to re-calibrate the timestamps on a regular basis.

        Valid Usage (Implicit)
        • device must be a valid VkDevice handle
        • pTimestampInfos must be a valid pointer to an array of timestampCount valid VkCalibratedTimestampInfoEXT structures
        • pTimestamps must be a valid pointer to an array of timestampCount uint64_t values
        • pMaxDeviation must be a valid pointer to a uint64_t value
        • timestampCount must be greater than 0
        Return Codes
        On success, this command returns
        On failure, this command returns
        See Also

        VkCalibratedTimestampInfoEXT

        Parameters:
        device - the logical device used to perform the query.
        pTimestampInfos - a pointer to an array of timestampCount number of structures of type VkCalibratedTimestampInfoEXT, describing the time domains the calibrated timestamps should be captured from.
        pTimestamps - a pointer to an array of timestampCount number of 64-bit unsigned integer values in which the requested calibrated timestamp values are returned.
        pMaxDeviation - a pointer to a 64-bit unsigned integer value in which the strictly positive maximum deviation, in nanoseconds, of the calibrated timestamp values is returned.