starpu-max/examples/axpy/axpy_opencl.c

/* StarPU --- Runtime system for heterogeneous multicore architectures.
 *
 * Copyright (C) 2012-2021  Université de Bordeaux, CNRS (LaBRI UMR 5800), Inria
 *
 * StarPU is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * StarPU is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * See the GNU Lesser General Public License in COPYING.LGPL for more details.
 */

/* OpenCL codelet for axpy */

#include <starpu.h>
#include "axpy.h"

extern struct starpu_opencl_program opencl_program;

void axpy_opencl(void *buffers[], void *_args)
{
	TYPE *alpha = _args;
	int id, devid;
        cl_int err;
	cl_kernel kernel;
	cl_command_queue queue;

	unsigned n = STARPU_VECTOR_GET_NX(buffers[0]);
	cl_mem x = (cl_mem) STARPU_VECTOR_GET_DEV_HANDLE(buffers[0]);
	unsigned x_offset = STARPU_VECTOR_GET_OFFSET(buffers[0]);
	cl_mem y = (cl_mem) STARPU_VECTOR_GET_DEV_HANDLE(buffers[1]);
	unsigned y_offset = STARPU_VECTOR_GET_OFFSET(buffers[1]);

	id = starpu_worker_get_id_check();
	devid = starpu_worker_get_devid(id);

	err = starpu_opencl_load_kernel(&kernel, &queue, &opencl_program, "_axpy_opencl", devid);
	if (err != CL_SUCCESS)
		STARPU_OPENCL_REPORT_ERROR(err);

	err = clSetKernelArg(kernel, 0, sizeof(x), &x);
	err|= clSetKernelArg(kernel, 1, sizeof(x_offset), &x_offset);
	err|= clSetKernelArg(kernel, 2, sizeof(y), &y);
	err|= clSetKernelArg(kernel, 3, sizeof(y_offset), &y_offset);
	err|= clSetKernelArg(kernel, 4, sizeof(n), &n);
	err|= clSetKernelArg(kernel, 5, sizeof(*alpha), alpha);
	if (err)
		STARPU_OPENCL_REPORT_ERROR(err);

	{
		size_t global=n;
		size_t local;
                size_t s;
                cl_device_id device;

                starpu_opencl_get_device(devid, &device);

                err = clGetKernelWorkGroupInfo (kernel, device, CL_KERNEL_WORK_GROUP_SIZE, sizeof(local), &local, &s);
                if (err != CL_SUCCESS)
			STARPU_OPENCL_REPORT_ERROR(err);
                if (local > global)
			local=global;
                else
                        global = (global + local-1) / local * local;

		err = clEnqueueNDRangeKernel(queue, kernel, 1, NULL, &global, &local, 0, NULL, NULL);
		if (err != CL_SUCCESS)
			STARPU_OPENCL_REPORT_ERROR(err);
	}
	starpu_opencl_release_kernel(kernel);
}