vkGetPhysicalDeviceCalibrateableTimeDomainsEXT - Query calibrateable time domains

Parameters

• PhysicalDevice is the physical device from which to query the set of calibrateable time domains.

• pTimeDomainCount is a pointer to an integer related to the number of calibrateable time domains available or queried, as described below.
• pTimeDomains is either NULL or a pointer to an array of TimeDomainEXT values, indicating the supported calibrateable time domains.

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 PhysicalDevice 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 TimeDomainEXT values

Return Codes

Success

• SUCCESS
• INCOMPLETE

Failure

• ERROR_OUT_OF_HOST_MEMORY
• ERROR_OUT_OF_DEVICE_MEMORY

See Also

PhysicalDevice, TimeDomainEXT

vkGetCalibratedTimestampsEXT - Query calibrated timestamps

Parameters

• Device is the logical device used to perform the query.

• timestampCount is the number of timestamps to query.
• pTimestampInfos is a pointer to an array of timestampCount CalibratedTimestampInfoEXT structures, describing the time domains the calibrated timestamps should be captured from.
• pTimestamps is a pointer to an array of timestampCount 64-bit unsigned integer values in which the requested calibrated timestamp values are returned.
• pMaxDeviation is 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.

Description

Note

The maximum deviation may vary between calls to getCalibratedTimestampsEXT 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.

Return Codes

Success

• SUCCESS

Failure

• ERROR_OUT_OF_HOST_MEMORY
• ERROR_OUT_OF_DEVICE_MEMORY

See Also

CalibratedTimestampInfoEXT, Device

VkCalibratedTimestampInfoEXT - Structure specifying the input parameters of a calibrated timestamp query

Valid Usage (Implicit)

See Also

StructureType, TimeDomainEXT, getCalibratedTimestampsEXT

VkTimeDomainEXT - Supported time domains

Description

struct timespec tv;
clock_gettime(CLOCK_MONOTONIC, &tv);
return tv.tv_nsec + tv.tv_sec*1000000000ull;

struct timespec tv;
clock_gettime(CLOCK_MONOTONIC_RAW, &tv);
return tv.tv_nsec + tv.tv_sec*1000000000ull;

LARGE_INTEGER counter;
QueryPerformanceCounter(&counter);
return counter.QuadPart;

See Also

CalibratedTimestampInfoEXT, getPhysicalDeviceCalibrateableTimeDomainsEXT