clGetEventProfilingInfo
clGetEventProfilingInfo
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clGetEventProfilingInfo Returns profiling information for the command associated with event if profiling is enabled.

##

cl_int `clGetEventProfilingInfo` cl_event event cl_profiling_info param_name size_t param_value_size void*param_value size_t*param_value_size_ret

## Parameters

`event`

  Specifies the event object.

`param_name`

  Specifies the profiling data to query. The list of supported `param_name` types and the information returned in `param_value` by `clGetEventProfilingInfo` is described in the table of parameter queries below.

`param_value_size`

  Specifies the size in bytes of memory pointed to by `param_value`. This size must be ≥ size of return type as described in the table below.

`param_value`

  A pointer to memory where the appropriate result being queried is returned. if `param_value` is NULL, it is ignored.

`param_value_size_ret`

  Returns the actual size in bytes of data copied to `param_value`. If `param_value_size_ret` is NULL, it is ignored.

  The following is a table of `clGetEventProfilingInfo` parameter queries

  cl_profiling_info | Return Type | Info. returned in `param_value`
  --- | --- | ---
  `CL_PROFILING_COMMAND_QUEUED` | cl_ulong | A 64-bit value that describes the current device time counter in nanoseconds when the command identified by `event` is enqueued in a command-queue by the host.
  `CL_PROFILING_COMMAND_SUBMIT` | cl_ulong | A 64-bit value that describes the current device time counter in nanoseconds when the command identified by `event` that has been enqueued is submitted by the host to the device associated with the command-queue.
  `CL_PROFILING_COMMAND_START` | cl_ulong | A 64-bit value that describes the current device time counter in nanoseconds when the command identified by `event` starts execution on the device.
  `CL_PROFILING_COMMAND_END` | cl_ulong | A 64-bit value that describes the current device time counter in nanoseconds when the command identified by `event` has finished execution on the device.

## Notes

The unsigned 64-bit values returned can be used to measure the time in nano-seconds consumed by OpenCL commands.

OpenCL devices are required to correctly track time across changes in device frequency and power states. The `CL_DEVICE_PROFILING_TIMER_RESOLUTION` specifies the resolution of the timer i.e. the number of nanoseconds elapsed before the timer is incremented.

Event objects can be used to capture profiling information that measure execution time of a command. Profiling of OpenCL commands can be enabled either by using a command-queue created with `CL_QUEUE_PROFILING_ENABLE` flag set in `properties` argument to clCreateCommandQueue.

## Errors

Returns CL_SUCCESS if the function is executed successfully and the profiling information has been recorded. Otherwise, it returns one of the following errors:

- CL_PROFILING_INFO_NOT_AVAILABLE if the `CL_QUEUE_PROFILING_ENABLE` flag is not set for the command-queue, if the execution status of the command identified by `event` is not `CL_COMPLETE` or if `event` is a user event object.
- CL_INVALID_VALUE if `param_name` is not valid, or if size in bytes specified by `param_value_size` is < size of return type as described in the above table and `param_value` is not NULL.
- CL_INVALID_EVENT if `event` is a not a valid event object.
- CL_OUT_OF_RESOURCES if there is a failure to allocate resources required by the OpenCL implementation on the device.
- CL_OUT_OF_HOST_MEMORY if there is a failure to allocate resources required by the OpenCL implementation on the host.

## Specification

OpenCL Specification

## Also see

clCreateCommandQueue

##