/*
 * This file is part of the StarPU Handbook.
 * Copyright (C) 2009--2011  Universit@'e de Bordeaux 1
 * Copyright (C) 2010, 2011, 2012, 2013  Centre National de la Recherche Scientifique
 * Copyright (C) 2011, 2012 Institut National de Recherche en Informatique et Automatique
 * See the file version.doxy for copying conditions.
 */

/*! \defgroup API_OpenCL_Extensions OpenCL Extensions

\def STARPU_USE_OPENCL
\ingroup API_OpenCL_Extensions
This macro is defined when StarPU has been installed with
OpenCL support. It should be used in your code to detect the
availability of OpenCL as shown in \ref FullSourceCodeVectorScal.

\struct starpu_opencl_program
\ingroup API_OpenCL_Extensions
Stores the OpenCL programs as compiled for the different OpenCL
devices.
\var starpu_opencl_program::programs
Stores each program for each OpenCL device.

@name Writing OpenCL kernels
\ingroup API_OpenCL_Extensions

\fn void starpu_opencl_get_context(int devid, cl_context *context)
\ingroup API_OpenCL_Extensions
Places the OpenCL context of the device designated by \p devid
into \p context.

\fn void starpu_opencl_get_device(int devid, cl_device_id *device)
\ingroup API_OpenCL_Extensions
Places the cl_device_id corresponding to \p devid in \p device.

\fn void starpu_opencl_get_queue(int devid, cl_command_queue *queue)
\ingroup API_OpenCL_Extensions
Places the command queue of the device designated by \p devid
into \p queue.

\fn void starpu_opencl_get_current_context(cl_context *context)
\ingroup API_OpenCL_Extensions
Return the context of the current worker.

\fn void starpu_opencl_get_current_queue(cl_command_queue *queue)
\ingroup API_OpenCL_Extensions
Return the computation kernel command queue of the current
worker.

\fn int starpu_opencl_set_kernel_args(cl_int *err, cl_kernel *kernel, ...)
\ingroup API_OpenCL_Extensions
Sets the arguments of a given kernel. The list of arguments
must be given as <c>(size_t size_of_the_argument, cl_mem *
pointer_to_the_argument)</c>. The last argument must be 0. Returns the
number of arguments that were successfully set. In case of failure,
returns the id of the argument that could not be set and err is set to
the error returned by OpenCL. Otherwise, returns the number of
arguments that were set.

Here an example:
\code{.c}
int n;
cl_int err;
cl_kernel kernel;
n = starpu_opencl_set_kernel_args(&err, 2, &kernel,
                                  sizeof(foo), &foo,
                                  sizeof(bar), &bar,
                                  0);
if (n != 2)
   fprintf(stderr, "Error : %d\n", err);
\endcode

@name Compiling OpenCL kernels
\ingroup API_OpenCL_Extensions

Source codes for OpenCL kernels can be stored in a file or in a
string. StarPU provides functions to build the program executable for
each available OpenCL device as a cl_program object. This program
executable can then be loaded within a specific queue as explained in
the next section. These are only helpers, Applications can also fill a
starpu_opencl_program array by hand for more advanced use (e.g.
different programs on the different OpenCL devices, for relocation
purpose for instance).

\fn int starpu_opencl_load_opencl_from_file(const char *source_file_name, struct starpu_opencl_program *opencl_programs, const char *build_options)
\ingroup API_OpenCL_Extensions
This function compiles an OpenCL source code stored in a file.

\fn int starpu_opencl_load_opencl_from_string(const char *opencl_program_source, struct starpu_opencl_program *opencl_programs, const char *build_options)
\ingroup API_OpenCL_Extensions
This function compiles an OpenCL source code stored in a string.

\fn int starpu_opencl_unload_opencl(struct starpu_opencl_program *opencl_programs)
\ingroup API_OpenCL_Extensions
This function unloads an OpenCL compiled code.

\fn void starpu_opencl_load_program_source(const char *source_file_name, char *located_file_name, char *located_dir_name, char *opencl_program_source)
\ingroup API_OpenCL_Extensions
Store the contents of the file \p source_file_name in the buffer
\p opencl_program_source. The file \p source_file_name can be located in the
current directory, or in the directory specified by the environment
variable \ref STARPU_OPENCL_PROGRAM_DIR, or
in the directory <c>share/starpu/opencl</c> of the installation
directory of StarPU, or in the source directory of StarPU. When the
file is found, \p located_file_name is the full name of the file as it
has been located on the system, \p located_dir_name the directory
where it has been located. Otherwise, they are both set to the empty
string.

\fn int starpu_opencl_compile_opencl_from_file(const char *source_file_name, const char *build_options)
\ingroup API_OpenCL_Extensions
Compile the OpenCL kernel stored in the file \p source_file_name
with the given options \p build_options and stores the result in the
directory <c>$STARPU_HOME/.starpu/opencl</c> with the same filename as
\p source_file_name. The compilation is done for every OpenCL device,
and the filename is suffixed with the vendor id and the device id of
the OpenCL device.

\fn int starpu_opencl_compile_opencl_from_string(const char *opencl_program_source, const char *file_name, const char *build_options)
\ingroup API_OpenCL_Extensions
Compile the OpenCL kernel in the string \p opencl_program_source
with the given options \p build_options and stores the result in the
directory <c>$STARPU_HOME/.starpu/opencl</c> with the filename \p
file_name. The compilation is done for every OpenCL device, and the
filename is suffixed with the vendor id and the device id of the
OpenCL device.

\fn int starpu_opencl_load_binary_opencl(const char *kernel_id, struct starpu_opencl_program *opencl_programs)
\ingroup API_OpenCL_Extensions
Compile the binary OpenCL kernel identified with \p kernel_id.
For every OpenCL device, the binary OpenCL kernel will be loaded from
the file
<c>$STARPU_HOME/.starpu/opencl/\<kernel_id\>.\<device_type\>.vendor_id_\<vendor_id\>_device_id_\<device_id\></c>.

@name Loading OpenCL kernels
\ingroup API_OpenCL_Extensions

\fn int starpu_opencl_load_kernel(cl_kernel *kernel, cl_command_queue *queue, struct starpu_opencl_program *opencl_programs, const char *kernel_name, int devid)
\ingroup API_OpenCL_Extensions
Create a kernel \p kernel for device \p devid, on its computation
command queue returned in \p queue, using program \p opencl_programs
and name \p kernel_name.

\fn int starpu_opencl_release_kernel(cl_kernel kernel)
\ingroup API_OpenCL_Extensions
Release the given \p kernel, to be called after kernel execution.

@name OpenCL statistics

\fn int starpu_opencl_collect_stats(cl_event event)
\ingroup API_OpenCL_Extensions
This function allows to collect statistics on a kernel execution.
After termination of the kernels, the OpenCL codelet should call this
function to pass it the even returned by clEnqueueNDRangeKernel, to
let StarPU collect statistics about the kernel execution (used cycles,
consumed power).

@name OpenCL utilities
\ingroup API_OpenCL_Extensions

\fn const char *starpu_opencl_error_string(cl_int status)
\ingroup API_OpenCL_Extensions
Return the error message in English corresponding to \p status, an OpenCL
error code.

\fn void starpu_opencl_display_error(const char *func, const char *file, int line, const char *msg, cl_int status)
\ingroup API_OpenCL_Extensions
Given a valid error status, prints the corresponding error message on
stdout, along with the given function name \p func, the given filename
\p file, the given line number \p line and the given message \p msg.

\def STARPU_OPENCL_DISPLAY_ERROR(status)
\ingroup API_OpenCL_Extensions
Call the function starpu_opencl_display_error() with the given error
\p status, the current function name, current file and line number,
and a empty message.

\fn void starpu_opencl_report_error(const char *func, const char *file, int line, const char *msg, cl_int status)
\ingroup API_OpenCL_Extensions
Call the function starpu_opencl_display_error() and abort.

\def STARPU_OPENCL_REPORT_ERROR(status)
\ingroup API_OpenCL_Extensions
Call the function starpu_opencl_report_error() with the given error \p
status, with the current function name, current file and line number,
and a empty message.

\def STARPU_OPENCL_REPORT_ERROR_WITH_MSG(msg, status)
\ingroup API_OpenCL_Extensions
Call the function starpu_opencl_report_error() with the given \p msg
and the given error \p status, with the current function name, current
file and line number.

\fn cl_int starpu_opencl_allocate_memory(cl_mem *addr, size_t size, cl_mem_flags flags)
\ingroup API_OpenCL_Extensions
Allocate \p size bytes of memory, stored in \p addr. \p flags must be a valid
combination of cl_mem_flags values.

\fn cl_int starpu_opencl_copy_ram_to_opencl(void *ptr, unsigned src_node, cl_mem buffer, unsigned dst_node, size_t size, size_t offset, cl_event *event, int *ret)
\ingroup API_OpenCL_Extensions
Copy \p size bytes from the given \p ptr on RAM \p src_node to the
given \p buffer on OpenCL \p dst_node. \p offset is the offset, in
bytes, in \p buffer. if \p event is <c>NULL</c>, the copy is
synchronous, i.e the queue is synchronised before returning. If not
<c>NULL</c>, \p event can be used after the call to wait for this
particular copy to complete. This function returns <c>CL_SUCCESS</c>
if the copy was successful, or a valid OpenCL error code otherwise.
The integer pointed to by \p ret is set to <c>-EAGAIN</c> if the
asynchronous launch was successful, or to 0 if \p event was
<c>NULL</c>.

\fn cl_int starpu_opencl_copy_opencl_to_ram(cl_mem buffer, unsigned src_node, void *ptr, unsigned dst_node, size_t size, size_t offset, cl_event *event, int *ret)
\ingroup API_OpenCL_Extensions
Copy \p size bytes asynchronously from the given \p buffer on OpenCL
\p src_node to the given \p ptr on RAM \p dst_node. \p offset is the
offset, in bytes, in \p buffer. if \p event is <c>NULL</c>, the copy
is synchronous, i.e the queue is synchronised before returning. If not
<c>NULL</c>, \p event can be used after the call to wait for this
particular copy to complete. This function returns <c>CL_SUCCESS</c>
if the copy was successful, or a valid OpenCL error code otherwise.
The integer pointed to by \p ret is set to <c>-EAGAIN</c> if the
asynchronous launch was successful, or to 0 if \p event was
<c>NULL</c>.

\fn cl_int starpu_opencl_copy_opencl_to_opencl(cl_mem src, unsigned src_node, size_t src_offset, cl_mem dst, unsigned dst_node, size_t dst_offset, size_t size, cl_event *event, int *ret)
\ingroup API_OpenCL_Extensions
Copy \p size bytes asynchronously from byte offset \p src_offset of \p
src on OpenCL \p src_node to byte offset \p dst_offset of \p dst on
OpenCL \p dst_node. if \p event is <c>NULL</c>, the copy is
synchronous, i.e. the queue is synchronised before returning. If not
<c>NULL</c>, \p event can be used after the call to wait for this
particular copy to complete. This function returns <c>CL_SUCCESS</c>
if the copy was successful, or a valid OpenCL error code otherwise.
The integer pointed to by \p ret is set to <c>-EAGAIN</c> if the
asynchronous launch was successful, or to 0 if \p event was
<c>NULL</c>.

\fn cl_int starpu_opencl_copy_async_sync(uintptr_t src, size_t src_offset, unsigned src_node, uintptr_t dst, size_t dst_offset, unsigned dst_node, size_t size, cl_event *event)
\ingroup API_OpenCL_Extensions
Copy \p size bytes from byte offset \p src_offset of \p src on \p
src_node to byte offset \p dst_offset of \p dst on \p dst_node. if \p
event is <c>NULL</c>, the copy is synchronous, i.e. the queue is
synchronised before returning. If not <c>NULL</c>, \p event can be
used after the call to wait for this particular copy to complete. The
function returns <c>-EAGAIN</c> if the asynchronous launch was
successfull. It returns 0 if the synchronous copy was successful, or
fails otherwise.

*/
