select.c

#include "opencl_lab2.h"

int deviceComparator(const cl_device_id *d1, const cl_device_id *d2) {
    cl_device_type type1, type2;
    cl_bool mem1, mem2;

    clGetDeviceInfo(*d1, CL_DEVICE_TYPE, sizeof(cl_device_type), &type1, NULL);
    clGetDeviceInfo(*d2, CL_DEVICE_TYPE, sizeof(cl_device_type), &type2, NULL);

    if (type1 == CL_DEVICE_TYPE_CPU) {
        return type2 != CL_DEVICE_TYPE_CPU;
    } else if (type2 == CL_DEVICE_TYPE_CPU) {
        return -1;
    }

    clGetDeviceInfo(*d1, CL_DEVICE_HOST_UNIFIED_MEMORY, sizeof(cl_bool), &mem1, NULL);
    clGetDeviceInfo(*d2, CL_DEVICE_HOST_UNIFIED_MEMORY, sizeof(cl_bool), &mem2, NULL);

    if (mem1 == CL_FALSE) {
        return -(mem2 != CL_FALSE);
    } else {
        return mem2 != CL_TRUE;
    }
}

cl_device_id getPreferredDevice(int index) {
    cl_int err;
    cl_uint numPlatforms;

    err = clGetPlatformIDs(0, NULL, &numPlatforms);

    if (checkErr(err, "Unable to get platform count")) {
        return 0;
    }

    //printf("Platforms: %i\n", numPlatforms);

    cl_platform_id platform[numPlatforms];
    err = clGetPlatformIDs(numPlatforms, platform, NULL);

    if (checkErr(err, "Unable to get platforms")) {
        return 0;
    }

//    printf("Detected %d OpenCL platforms:\n", numPlatforms);
//    printf("----------------------------------------\n");

    // calculate general number of devices
    cl_uint deviceCount = 0;
    for (cl_uint i = 0; i < numPlatforms; i++) {
        cl_uint numDevices;
        err = clGetDeviceIDs(platform[i], CL_DEVICE_TYPE_GPU, 0, NULL, &numDevices);
        if (err != CL_SUCCESS && err != CL_DEVICE_NOT_FOUND) {
            printf("Unable to get GPU count: %d", err);
            return 0;
        }
        deviceCount += numDevices;
        err = clGetDeviceIDs(platform[i], CL_DEVICE_TYPE_CPU, 0, NULL, &numDevices);
        if (err != CL_SUCCESS && err != CL_DEVICE_NOT_FOUND) {
            printf("Unable to get CPU count: %d", err);
            return 0;
        }
        deviceCount += numDevices;
    }

    if (deviceCount == 0) {
        printf("There are no OpenCL devices available\n");
        return 0;
    }

    cl_device_id deviceIds[deviceCount];
    cl_uint deviceIndex = 0;

    for (cl_uint i = 0; i < numPlatforms; i++) {
        cl_uint numDevices;
        err = clGetDeviceIDs(platform[i], CL_DEVICE_TYPE_GPU, 0, NULL, &numDevices);

        if (err == CL_SUCCESS) {
            cl_device_id gpus[numDevices];
            err = clGetDeviceIDs(platform[i], CL_DEVICE_TYPE_GPU, numDevices, gpus, 0);

            if (err == CL_SUCCESS) {
                for (cl_uint j = 0; j < numDevices; j++) {
                    // add to main device list
                    deviceIds[deviceIndex++] = gpus[j];
                }
            }
        }

        err = clGetDeviceIDs(platform[i], CL_DEVICE_TYPE_CPU, 0, NULL, &numDevices);

        if (err == CL_SUCCESS) {
            cl_device_id cpus[numDevices];
            err = clGetDeviceIDs(platform[i], CL_DEVICE_TYPE_CPU, numDevices, cpus, 0);

            if (err == CL_SUCCESS) {
                for (cl_uint j = 0; j < numDevices; j++) {
                    // add to main device list
                    deviceIds[deviceIndex++] = cpus[j];
                }
            }
        }
    }

    qsort(deviceIds, deviceCount, sizeof(cl_device_id), (int (*)(const void *, const void *)) deviceComparator);

    //printf("deviceCount: %i\n", deviceCount);

    if (index < 0 || index >= deviceCount) {
        index = 0;
    }

    cl_device_id device = deviceIds[index];

    printf("----------------------------------------\n");

    // Device name
    size_t deviceNameSize;
    err = clGetDeviceInfo(device, CL_DEVICE_NAME, 0, NULL, &deviceNameSize);

    if (err != CL_SUCCESS) {
        printf("Can't get device name for device %d. Error code: %d", device, err);
        return 0;
    }

    cl_uchar deviceName[deviceNameSize];
    err = clGetDeviceInfo(device, CL_DEVICE_NAME, deviceNameSize, deviceName, 0);

    if (err == CL_SUCCESS) {
        printf("Running on device: %s\n", deviceName);
    } else {
        printf("Can't get device name for device %d. Error code: %d", device, err);
        return 0;
    }

    printf("----------------------------------------\n");

    return deviceIds[index];
}