clEnqueueNDRangeKernel - Enqueues a command to execute a kernel on a device.
const size_t *global_work_offset,
const size_t *global_work_size,
const size_t *local_work_size,
const cl_event *event_wait_list,
A valid command-queue. The kernel will be queued for
execution on the device associated with command_queue.
A valid kernel object. The OpenCL context associated with
kernel and command_queue must be the same.
The number of dimensions used to specify the global
work-items and work-items in the work-group. work_dim must be greater
than zero and less than or equal to
global_work_offset can be used to specify an array of
work_dim unsigned values that describe the offset used to calculate
the global ID of a work-item. If global_work_offset is NULL, the
global IDs start at offset (0, 0, ... 0).
Points to an array of work_dim unsigned values
that describe the number of global work-items in work_dim dimensions
that will execute the kernel function. The total number of global work-items
is computed as global_work_size *...*
global_work_size[work_dim - 1].
Points to an array of work_dim
that describe the number of work-items that make up a work-group (also
referred to as the size of the work-group) that will execute the kernel
specified by kernel
. The total number of work-items in a work-group is
computed as local_work_size
 *... *
- 1]. The total number of work-items in
the work-group must be less than or equal to the
value specified in table of OpenCL Device
Queries for clGetDeviceInfo
(3clc) and the number of work-items
specified in local_work_size
- 1] must be less than or equal to the
corresponding values specified by CL_DEVICE_MAX_WORK_ITEM_SIZES
- 1]. The explicitly
will be used to determine how to break the
global work-items specified by global_work_size
work-group instances. If local_work_size
is specified, the values
specified in global_work_size
- 1] must be evenly divisible by the
corresponding values specified in local_work_size
local_work_size can also be a NULL value in which case the
OpenCL implementation will determine how to be break the global work-items
into appropriate work-group instances.
Specify events that need to complete before this
particular command can be executed. If event_wait_list is NULL, then
this particular command does not wait on any event to complete. If
event_wait_list is NULL, num_events_in_wait_list must be 0. If
event_wait_list is not NULL, the list of events pointed to by
event_wait_list must be valid and num_events_in_wait_list must
be greater than 0. The events specified in event_wait_list act as
synchronization points. The context associated with events in
event_wait_list and command_queue must be the same. The memory
associated with event_wait_list can be reused or freed after the
Returns an event object that identifies this particular
kernel execution instance. Event objects are unique and can be used to
identify a particular kernel execution instance later on. If event is
NULL, no event will be created for this kernel execution instance and
therefore it will not be possible for the application to query or queue a wait
for this particular kernel execution instance.
The work-group size to be used for kernel can also be specified in the
program source using the attribute(3clc) ((reqd_work_group_size(X, Y,
Z))) qualifier. In this case the size of work group specified by
local_work_size must match the value specified by the
reqd_work_group_size attribute(3clc) qualifier.
These work-group instances are executed in parallel across
multiple compute units or concurrently on the same compute unit.
Each work-item is uniquely identified by a global identifier. The
global ID, which can be read inside the kernel, is computed using the value
given by global_work_size and global_work_offset. In addition,
a work-item is also identified within a work-group by a unique local ID. The
local ID, which can also be read by the kernel, is computed using the value
given by local_work_size. The starting local ID is always (0, 0, ...
Returns CL_SUCCESS if the kernel execution was successfully queued. Otherwise,
it returns one of the following errors:
•CL_INVALID_PROGRAM_EXECUTABLE if there is no
successfully built program executable available for device associated with
•CL_INVALID_COMMAND_QUEUE if command_queue
is not a valid command-queue.
•CL_INVALID_KERNEL if kernel is not a valid
•CL_INVALID_CONTEXT if context associated with
command_queue and kernel is not the same or if the context
associated with command_queue and events in event_wait_list are
not the same.
•CL_INVALID_KERNEL_ARGS if the kernel argument
values have not been specified.
•CL_INVALID_WORK_DIMENSION if work_dim is
not a valid value (i.e. a value between 1 and 3).
global_work_size is NULL, or if any of the values specified in
global_work_size, ...global_work_size [work_dim - 1]
are 0 or exceed the range given by the sizeof(size_t) for the device on which
the kernel execution will be enqueued.
•CL_INVALID_GLOBAL_OFFSET if the value specified
in global_work_size + the corresponding values in
global_work_offset for any dimensions is greater than the
sizeof(size_t) for the device on which the kernel execution will be
local_work_size is specified and number of work-items specified by
global_work_size is not evenly divisable by size of work-group given by
local_work_size or does not match the work-group size specified for
kernel using the functionQualifiers(3clc)
((reqd_work_group_size(X, Y, Z))) qualifier in program source.
local_work_size is specified and the total number of work-items in the
work-group computed as local_work_size *...
local_work_size[work_dim - 1] is greater than the value
specified by CL_DEVICE_MAX_WORK_GROUP_SIZE in the table of OpenCL
Device Queries for clGetDeviceInfo(3clc).
local_work_size is NULL and the functionQualifiers(3clc)
((reqd_work_group_size(X, Y, Z))) qualifier is used to declare the work-group
size for kernel in the program source.
•CL_INVALID_WORK_ITEM_SIZE if the number of
work-items specified in any of local_work_size, ...
local_work_size[work_dim - 1] is greater than the corresponding
values specified by CL_DEVICE_MAX_WORK_ITEM_SIZES, ....
CL_DEVICE_MAX_WORK_ITEM_SIZES[work_dim - 1].
•CL_MISALIGNED_SUB_BUFFER_OFFSET if a sub-buffer
object is specified as the value for an argument that is a buffer object and
the offset specified when the sub-buffer object is created is not
aligned to CL_DEVICE_MEM_BASE_ADDR_ALIGN value for device associated
•CL_INVALID_IMAGE_SIZE if an image object is
specified as an argument value and the image dimensions (image width, height,
specified or compute row and/or slice pitch) are not supported by device
associated with queue.
•CL_INVALID_IMAGE_FORMAT if an image object is
specified as an argument value and the image format (image channel order and
data type) is not supported by device associated with queue.
•CL_OUT_OF_RESOURCES if there is a failure to
queue the execution instance of kernel on the command-queue because of
insufficient resources needed to execute the kernel. For example, the
explicitly specified local_work_size causes a failure to execute the
kernel because of insufficient resources such as registers or local memory.
Another example would be the number of read-only image args used in
kernel exceed the CL_DEVICE_MAX_READ_IMAGE_ARGS value for device
or the number of write-only image args used in kernel exceed the
CL_DEVICE_MAX_WRITE_IMAGE_ARGS value for device or the number of
samplers used in kernel exceed CL_DEVICE_MAX_SAMPLERS for
•CL_MEM_OBJECT_ALLOCATION_FAILURE if there is a
failure to allocate memory for data store associated with image or buffer
objects specified as arguments to kernel.
event_wait_list is NULL and num_events_in_wait_list > 0, or
event_wait_list is not NULL and num_events_in_wait_list is 0, or
if event objects in event_wait_list are not valid events.
•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.
The Khronos Group
Copyright © 2007-2011 The Khronos Group Inc.
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction,
including without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to permit
persons to whom the Materials are furnished to do so, subject to the condition
that this copyright notice and permission notice shall be included in all
copies or substantial portions of the Materials.
- OpenCL Specification
page 169, section 5.8 - Executing Kernels (updated for
1.2 rev 14)