- type CLCommandQueue = Ptr ()
- data CLCommandQueueProperty
- clCreateCommandQueue :: CLContext -> CLDeviceID -> [CLCommandQueueProperty] -> IO CLCommandQueue
- clRetainCommandQueue :: CLCommandQueue -> IO Bool
- clReleaseCommandQueue :: CLCommandQueue -> IO Bool
- clGetCommandQueueContext :: CLCommandQueue -> IO CLContext
- clGetCommandQueueDevice :: CLCommandQueue -> IO CLDeviceID
- clGetCommandQueueReferenceCount :: CLCommandQueue -> IO CLuint
- clGetCommandQueueProperties :: CLCommandQueue -> IO [CLCommandQueueProperty]
- clSetCommandQueueProperty :: CLCommandQueue -> [CLCommandQueueProperty] -> Bool -> IO [CLCommandQueueProperty]
- clEnqueueReadBuffer :: Integral a => CLCommandQueue -> CLMem -> Bool -> a -> a -> Ptr () -> [CLEvent] -> IO CLEvent
- clEnqueueWriteBuffer :: Integral a => CLCommandQueue -> CLMem -> Bool -> a -> a -> Ptr () -> [CLEvent] -> IO CLEvent
- clEnqueueNDRangeKernel :: Integral a => CLCommandQueue -> CLKernel -> [a] -> [a] -> [CLEvent] -> IO CLEvent
- clEnqueueTask :: CLCommandQueue -> CLKernel -> [CLEvent] -> IO CLEvent
- clEnqueueMarker :: CLCommandQueue -> IO CLEvent
- clEnqueueWaitForEvents :: CLCommandQueue -> [CLEvent] -> IO ()
- clEnqueueBarrier :: CLCommandQueue -> IO ()
- clFlush :: CLCommandQueue -> IO Bool
- clFinish :: CLCommandQueue -> IO Bool
Types
type CLCommandQueue = Ptr ()Source
data CLCommandQueueProperty Source
-
CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE
, Determines whether the commands queued in the command-queue are executed in-order or out-of-order. If set, the commands in the command-queue are executed out-of-order. Otherwise, commands are executed in-order. -
CL_QUEUE_PROFILING_ENABLE
, Enable or disable profiling of commands in the command-queue. If set, the profiling of commands is enabled. Otherwise profiling of commands is disabled. SeeclGetEventProfilingInfo
for more information.
Command Queue Functions
clCreateCommandQueue :: CLContext -> CLDeviceID -> [CLCommandQueueProperty] -> IO CLCommandQueueSource
Create a command-queue on a specific device.
The OpenCL functions that are submitted to a command-queue are enqueued in the order the calls are made but can be configured to execute in-order or out-of-order. The properties argument in clCreateCommandQueue can be used to specify the execution order.
If the CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE
property of a command-queue is
not set, the commands enqueued to a command-queue execute in order. For example,
if an application calls clEnqueueNDRangeKernel
to execute kernel A followed by
a clEnqueueNDRangeKernel
to execute kernel B, the application can assume that
kernel A finishes first and then kernel B is executed. If the memory objects
output by kernel A are inputs to kernel B then kernel B will see the correct
data in memory objects produced by execution of kernel A. If the
CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE
property of a commandqueue is set, then
there is no guarantee that kernel A will finish before kernel B starts execution.
Applications can configure the commands enqueued to a command-queue to execute
out-of-order by setting the CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE
property of
the command-queue. This can be specified when the command-queue is created or
can be changed dynamically using clCreateCommandQueue
. In out-of-order
execution mode there is no guarantee that the enqueued commands will finish
execution in the order they were queued. As there is no guarantee that kernels
will be executed in order, i.e. based on when the clEnqueueNDRangeKernel
calls
are made within a command-queue, it is therefore possible that an earlier
clEnqueueNDRangeKernel
call to execute kernel A identified by event A may
execute and/or finish later than a clEnqueueNDRangeKernel
call to execute
kernel B which was called by the application at a later point in time. To
guarantee a specific order of execution of kernels, a wait on a particular event
(in this case event A) can be used. The wait for event A can be specified in the
event_wait_list argument to clEnqueueNDRangeKernel
for kernel B.
In addition, a wait for events or a barrier command can be enqueued to the command-queue. The wait for events command ensures that previously enqueued commands identified by the list of events to wait for have finished before the next batch of commands is executed. The barrier command ensures that all previously enqueued commands in a command-queue have finished execution before the next batch of commands is executed.
Similarly, commands to read, write, copy or map memory objects that are enqueued
after clEnqueueNDRangeKernel
, clEnqueueTask
or clEnqueueNativeKernel
commands are not guaranteed to wait for kernels scheduled for execution to have
completed (if the CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE
property is set). To
ensure correct ordering of commands, the event object returned by
clEnqueueNDRangeKernel
, clEnqueueTask
or clEnqueueNativeKernel
can be
used to enqueue a wait for event or a barrier command can be enqueued that must
complete before reads or writes to the memory object(s) occur.
clRetainCommandQueue :: CLCommandQueue -> IO BoolSource
Increments the command_queue reference count. clCreateCommandQueue
performs an implicit retain. This is very helpful for 3rd party libraries, which
typically get a command-queue passed to them by the application. However, it is
possible that the application may delete the command-queue without informing the
library. Allowing functions to attach to (i.e. retain) and release a
command-queue solves the problem of a command-queue being used by a library no
longer being valid. Returns True
if the function is executed successfully. It
returns False
if command_queue is not a valid command-queue.
clReleaseCommandQueue :: CLCommandQueue -> IO BoolSource
Decrements the command_queue reference count.
After the command_queue reference count becomes zero and all commands queued
to command_queue have finished (e.g., kernel executions, memory object
updates, etc.), the command-queue is deleted.
Returns True
if the function is executed successfully. It returns False
if command_queue is not a valid command-queue.
clGetCommandQueueContext :: CLCommandQueue -> IO CLContextSource
Return the context specified when the command-queue is created.
This function execute OpenCL clGetCommandQueueInfo with CL_QUEUE_CONTEXT
.
clGetCommandQueueDevice :: CLCommandQueue -> IO CLDeviceIDSource
Return the device specified when the command-queue is created.
This function execute OpenCL clGetCommandQueueInfo with CL_QUEUE_DEVICE
.
clGetCommandQueueReferenceCount :: CLCommandQueue -> IO CLuintSource
Return the command-queue reference count. The reference count returned should be considered immediately stale. It is unsuitable for general use in applications. This feature is provided for identifying memory leaks.
This function execute OpenCL clGetCommandQueueInfo with
CL_QUEUE_REFERENCE_COUNT
.
clGetCommandQueueProperties :: CLCommandQueue -> IO [CLCommandQueueProperty]Source
Return the currently specified properties for the command-queue. These
properties are specified by the properties argument in clCreateCommandQueue
, and can be changed by clSetCommandQueueProperty
.
This function execute OpenCL clGetCommandQueueInfo with
CL_QUEUE_PROPERTIES
.
clSetCommandQueueProperty :: CLCommandQueue -> [CLCommandQueueProperty] -> Bool -> IO [CLCommandQueueProperty]Source
Enable or disable the properties of a command-queue. Returns the
command-queue properties before they were changed by
clSetCommandQueueProperty
. As specified for clCreateCommandQueue
, the
CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE
command-queue property determines
whether the commands in a command-queue are executed in-order or
out-of-order. Changing this command-queue property will cause the OpenCL
implementation to block until all previously queued commands in command_queue
have completed. This can be an expensive operation and therefore changes to the
CL_QUEUE_OUT_OF_ORDER_EXEC_MODE_ENABLE
property should be only done when
absolutely necessary.
It is possible that a device(s) becomes unavailable after a context and command-queues that use this device(s) have been created and commands have been queued to command-queues. In this case the behavior of OpenCL API calls that use this context (and command-queues) are considered to be implementation-defined. The user callback function, if specified when the context is created, can be used to record appropriate information when the device becomes unavailable.
Memory Commands
clEnqueueReadBuffer :: Integral a => CLCommandQueue -> CLMem -> Bool -> a -> a -> Ptr () -> [CLEvent] -> IO CLEventSource
Enqueue commands to read from a buffer object to host memory. Calling
clEnqueueReadBuffer to read a region of the buffer object with the ptr argument
value set to host_ptr + offset, where host_ptr is a pointer to the memory region
specified when the buffer object being read is created with
CL_MEM_USE_HOST_PTR
, must meet the following requirements in order to avoid
undefined behavior:
- All commands that use this buffer object have finished execution before the read command begins execution
- The buffer object is not mapped
- The buffer object is not used by any command-queue until the read command has finished execution Errors
clEnqueueReadBuffer
returns the event if the function is executed
successfully. It can throw the following CLError
exceptions:
-
CL_INVALID_COMMAND_QUEUE
if command_queue is not a valid command-queue. -
CL_INVALID_CONTEXT
if the context associated with command_queue and buffer are not the same or if the context associated with command_queue and events in event_wait_list are not the same. -
CL_INVALID_MEM_OBJECT
if buffer is not a valid buffer object. -
CL_INVALID_VALUE
if the region being read specified by (offset, cb) is out of bounds or if ptr is a NULL value. -
CL_INVALID_EVENT_WAIT_LIST
if event_wait_list is NULL and num_events_in_wait_list greater than 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_MEM_OBJECT_ALLOCATION_FAILURE
if there is a failure to allocate memory for data store associated with buffer. -
CL_OUT_OF_HOST_MEMORY
if there is a failure to allocate resources required by the OpenCL implementation on the host.
clEnqueueWriteBuffer :: Integral a => CLCommandQueue -> CLMem -> Bool -> a -> a -> Ptr () -> [CLEvent] -> IO CLEventSource
Enqueue commands to write to a buffer object from host memory.Calling
clEnqueueWriteBuffer to update the latest bits in a region of the buffer object
with the ptr argument value set to host_ptr + offset, where host_ptr is a
pointer to the memory region specified when the buffer object being written is
created with CL_MEM_USE_HOST_PTR
, must meet the following requirements in
order to avoid undefined behavior:
- The host memory region given by (host_ptr + offset, cb) contains the latest bits when the enqueued write command begins execution.
- The buffer object is not mapped.
- The buffer object is not used by any command-queue until the write command has finished execution.
clEnqueueWriteBuffer
returns the Event if the function is executed
successfully. It can throw the following CLError
exceptions:
-
CL_INVALID_COMMAND_QUEUE
if command_queue is not a valid command-queue. -
CL_INVALID_CONTEXT
if the context associated with command_queue and buffer are not the same or if the context associated with command_queue and events in event_wait_list are not the same. -
CL_INVALID_MEM_OBJECT
if buffer is not a valid buffer object. -
CL_INVALID_VALUE
if the region being written specified by (offset, cb) is out of bounds or if ptr is a NULL value. -
CL_INVALID_EVENT_WAIT_LIST
if event_wait_list is NULL and num_events_in_wait_list greater than 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_MEM_OBJECT_ALLOCATION_FAILURE
if there is a failure to allocate memory for data store associated with buffer. -
CL_OUT_OF_HOST_MEMORY
if there is a failure to allocate resources required by the OpenCL implementation on the host.
Executing Kernels
clEnqueueNDRangeKernel :: Integral a => CLCommandQueue -> CLKernel -> [a] -> [a] -> [CLEvent] -> IO CLEventSource
Enqueues a command to execute a kernel on a device. 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 OpenCL 1.0, the starting global ID is always (0, 0, ... 0). 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, ... 0).
Returns the event if the kernel execution was successfully queued. It can throw
the following CLError
exceptions:
-
CL_INVALID_PROGRAM_EXECUTABLE
if there is no successfully built program executable available for device associated with command_queue. -
CL_INVALID_COMMAND_QUEUE
if command_queue is not a valid command-queue. -
CL_INVALID_KERNEL
if kernel is not a valid kernel object. -
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). -
CL_INVALID_WORK_GROUP_SIZE
if 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 __attribute__((reqd_work_group_size(X, Y, Z))) qualifier in program source. -
CL_INVALID_WORK_GROUP_SIZE
if local_work_size is specified and the total number of work-items in the work-group computed as local_work_size[0] *... local_work_size[work_dim - 1] is greater than the value specified byCL_DEVICE_MAX_WORK_GROUP_SIZE
in the table of OpenCL Device Queries for clGetDeviceInfo. -
CL_INVALID_WORK_GROUP_SIZE
if local_work_size is NULL and the __attribute__((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[0], ... local_work_size[work_dim - 1] is greater than the corresponding values specified byCL_DEVICE_MAX_WORK_ITEM_SIZES
[0], ....CL_DEVICE_MAX_WORK_ITEM_SIZES
[work_dim - 1]. -
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 theCL_DEVICE_MAX_READ_IMAGE_ARGS
value for device or the number of write-only image args used in kernel exceed theCL_DEVICE_MAX_WRITE_IMAGE_ARGS
value for device or the number of samplers used in kernel exceedCL_DEVICE_MAX_SAMPLERS
for device. -
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. -
CL_OUT_OF_HOST_MEMORY
if there is a failure to allocate resources required by the OpenCL implementation on the host.
clEnqueueTask :: CLCommandQueue -> CLKernel -> [CLEvent] -> IO CLEventSource
Enqueues a command to execute a kernel on a device. The kernel is executed using a single work-item.
clEnqueueTask
is equivalent to calling clEnqueueNDRangeKernel
with work_dim
= 1, global_work_offset = [], global_work_size[0] set to 1, and
local_work_size[0] set to 1.
Returns the evens if the kernel execution was successfully queued. It can throw
the following CLError
exceptions:
-
CL_INVALID_PROGRAM_EXECUTABLE
if there is no successfully built program executable available for device associated with command_queue. - 'CL_INVALID_COMMAND_QUEUE if' command_queue is not a valid command-queue.
-
CL_INVALID_KERNEL
if kernel is not a valid kernel object. -
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_GROUP_SIZE
if a work-group size is specified for kernel using the __attribute__((reqd_work_group_size(X, Y, Z))) qualifier in program source and is not (1, 1, 1). -
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. -
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. -
CL_OUT_OF_HOST_MEMORY
if there is a failure to allocate resources required by the OpenCL implementation on the host.
clEnqueueMarker :: CLCommandQueue -> IO CLEventSource
Enqueues a marker command to command_queue. The marker command returns an
event which can be used to queue a wait on this marker event i.e. wait for
all commands queued before the marker command to complete. Returns the event
if the function is successfully executed. It throw the CLError
exception
CL_INVALID_COMMAND_QUEUE
if command_queue is not a valid command-queue and
throw CL_OUT_OF_HOST_MEMORY
if there is a failure to allocate resources
required by the OpenCL implementation on the host.
clEnqueueWaitForEvents :: CLCommandQueue -> [CLEvent] -> IO ()Source
Enqueues a wait for a specific event or a list of events to complete before any future commands queued in the command-queue are executed. The context associated with events in event_list and command_queue must be the same.
It can throw the following CLError
exceptions:
-
CL_INVALID_COMMAND_QUEUE
if command_queue is not a valid command-queue. -
CL_INVALID_CONTEXT
if the context associated with command_queue and events in event_list are not the same. -
CL_INVALID_VALUE
if num_events is zero. -
CL_INVALID_EVENT
if event objects specified in event_list are not valid events. -
CL_OUT_OF_HOST_MEMORY
if there is a failure to allocate resources required by the OpenCL implementation on the host.
clEnqueueBarrier :: CLCommandQueue -> IO ()Source
clEnqueueBarrier
is a synchronization point that ensures that all queued
commands in command_queue have finished execution before the next batch of
commands can begin execution. It throws CL_INVALID_COMMAND_QUEUE
if
command_queue is not a valid command-queue and throws
CL_OUT_OF_HOST_MEMORY
if there is a failure to allocate resources required
by the OpenCL implementation on the host.
Flush and Finish
clFlush :: CLCommandQueue -> IO BoolSource
Issues all previously queued OpenCL commands in a command-queue to the
device associated with the command-queue. clFlush
only guarantees that all
queued commands to command_queue get issued to the appropriate device. There is
no guarantee that they will be complete after clFlush
returns.
clFlush
returns True
if the function call was executed successfully. It
returns False
if command_queue is not a valid command-queue or if there is a
failure to allocate resources required by the OpenCL implementation on the host.
Any blocking commands queued in a command-queue such as clEnqueueReadImage
or
clEnqueueReadBuffer
with blocking_read set to True
, clEnqueueWriteImage
or
clEnqueueWriteBuffer
with blocking_write set to True
, clEnqueueMapImage
or
clEnqueueMapBuffer
with blocking_map set to True
or clWaitForEvents
perform an implicit flush of the command-queue.
To use event objects that refer to commands enqueued in a command-queue as
event objects to wait on by commands enqueued in a different command-queue, the
application must call a clFlush
or any blocking commands that perform an
implicit flush of the command-queue where the commands that refer to these event
objects are enqueued.
clFinish :: CLCommandQueue -> IO BoolSource
Blocks until all previously queued OpenCL commands in a command-queue are
issued to the associated device and have completed.
clFinish
does not return until all queued commands in command_queue have
been processed and completed. clFinish
is also a synchronization point.
clFinish
returns True
if the function call was executed successfully. It
returns False
if command_queue is not a valid command-queue or if there is
a failure to allocate resources required by the OpenCL implementation on the
host.