Compose a programme using OpenCL and using local memory. Task: b=min(A+C)
I have a ready block diagram, but the teacher says that it shows everything sequentially, and we have a parallel programme and I don't know how to fix the block diagram.
I also want to know if I have written a programme using local memory correctly or not.
Link to image with block diagram:
https://www.imghippo.com/i/1704956923.jpg
#define _CRT_SECURE_NO_WARNINGS
#define CL_USE_DEPRECATED_OPENCL_1_2_APIS
#include <CL/cl.h>
#include <CL/cl_platform.h>
#include <iostream>
#include <cstdlib>
#include <stdio.h>
#define MAX_SOURCE_SIZE (0x100000)
#define LIST_SIZE 64
int main(void) {
int* A = new int[LIST_SIZE];
int* C = new int[LIST_SIZE];
int* B = new int[LIST_SIZE];
srand(time(0));
for (int i = 0; i < LIST_SIZE; i++) {
A[i] = (rand() % 200) / 2.;
C[i] = (rand() % 200) / 2.;
}
FILE* fp;
char* source_str;
size_t source_size;
fp = fopen("kernel.cl", "r");
if (!fp) {
fprintf(stderr, "Failed to load kernel.\n");
exit(1);
}
source_str = new char[MAX_SOURCE_SIZE];
source_size = fread(source_str, 1, MAX_SOURCE_SIZE, fp);
fclose(fp);
cl_platform_id platform_id = NULL;
cl_device_id device_id = NULL;
cl_uint ret_num_devices;
cl_uint ret_num_platforms;
cl_int ret = clGetPlatformIDs(1, &platform_id, &ret_num_platforms);
ret = clGetDeviceIDs(platform_id, CL_DEVICE_TYPE_DEFAULT, 1, &device_id, &ret_num_devices);
cl_context context = clCreateContext(NULL, 1, &device_id, NULL, NULL, &ret);
cl_command_queue command_queue = clCreateCommandQueueWithProperties(context, device_id, 0, &ret);
cl_mem a_mem_obj = clCreateBuffer(context, CL_MEM_READ_ONLY, LIST_SIZE * sizeof(int), NULL, &ret);
cl_mem c_mem_obj = clCreateBuffer(context, CL_MEM_READ_ONLY, LIST_SIZE * sizeof(int), NULL, &ret);
cl_mem b_mem_obj = clCreateBuffer(context, CL_MEM_WRITE_ONLY, LIST_SIZE * sizeof(int), NULL, &ret);
ret = clEnqueueWriteBuffer(command_queue, a_mem_obj, CL_TRUE, 0, LIST_SIZE * sizeof(int), A, 0, NULL, NULL);
ret = clEnqueueWriteBuffer(command_queue, c_mem_obj, CL_TRUE, 0, LIST_SIZE * sizeof(int), C, 0, NULL, NULL);
cl_program program = clCreateProgramWithSource(context, 1, (const char**)&source_str, (const size_t*)&source_size, &ret);
ret = clBuildProgram(program, 1, &device_id, NULL, NULL, NULL);
cl_kernel kernel = clCreateKernel(program, "krn", &ret);
size_t local_item_size = 64;
ret = clSetKernelArg(kernel, 0, sizeof(cl_mem), (void*)&a_mem_obj);
ret = clSetKernelArg(kernel, 1, sizeof(cl_mem), (void*)&c_mem_obj);
ret = clSetKernelArg(kernel, 2, sizeof(cl_mem), (void*)&b_mem_obj);
ret = clSetKernelArg(kernel, 3, local_item_size * sizeof(int), NULL);
size_t global_item_size = LIST_SIZE;
ret = clEnqueueNDRangeKernel(command_queue, kernel, 1, NULL, &global_item_size, &local_item_size, 0, NULL, NULL);
ret = clEnqueueReadBuffer(command_queue, b_mem_obj, CL_TRUE, 0, LIST_SIZE * sizeof(int), B, 0, NULL, NULL);
for (int i = 0; i < LIST_SIZE; i++) {
printf("%d. sum: %d\n", i, B[i]);
}
int min = B[0];
int minIndex = 0;
for (int i = 0; i < LIST_SIZE; i++) {
if (B[i] < min) {
min = B[i];
minIndex = i;
}
}
printf("\n\n%d. Minimum min(A+C) = %d\n", minIndex, min);
ret = clFlush(command_queue);
ret = clFinish(command_queue);
ret = clReleaseKernel(kernel);
ret = clReleaseProgram(program);
ret = clReleaseMemObject(a_mem_obj);
ret = clReleaseMemObject(c_mem_obj);
ret = clReleaseMemObject(b_mem_obj);
ret = clReleaseCommandQueue(command_queue);
ret = clReleaseContext(context);
delete[] source_str;
delete[] A;
delete[] B;
delete[] C;
return 0;
}
kernel.cl:
__kernel void krn(__global const int* A, __global const int* C, __global int* B) {
int i = get_global_id(0);
__local int localA[128];
__local int localC[128];
localA[i] = A[i];
localC[i] = C[i];
barrier(CLK_LOCAL_MEM_FENCE);
B[i] = localA[i] + localC[i];
}
What I have tried:
Made a wrong block diagram and wrote a programme