cuda.cc

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// Copyright (c) 2018, ETH Zurich and UNC Chapel Hill.
// All rights reserved.
//
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// Author: Johannes L. Schoenberger (jsch-at-demuc-dot-de)
 
#include "util/cuda.h"
 
#include <cuda_runtime.h>
 
#include <algorithm>
#include <iostream>
#include <vector>
 
#include "util/cudacc.h"
#include "util/logging.h"
 
namespace colmap {
namespace {
 
// Check whether the first Cuda device is better than the second.
bool CompareCudaDevice(const cudaDeviceProp& d1, const cudaDeviceProp& d2) {
    bool result = (d1.major > d2.major) ||
                  ((d1.major == d2.major) && (d1.minor > d2.minor)) ||
                  ((d1.major == d2.major) && (d1.minor == d2.minor) &&
                   (d1.multiProcessorCount > d2.multiProcessorCount));
    return result;
}
 
}  // namespace
 
int GetNumCudaDevices() {
    int num_cuda_devices = 0;
    cudaError_t error = cudaGetDeviceCount(&num_cuda_devices);
    if (error != cudaSuccess) {
        // CUDA initialization failed or no devices available
        return 0;
    }
    return num_cuda_devices;
}
 
void SetBestCudaDevice(const int gpu_index) {
    const int num_cuda_devices = GetNumCudaDevices();
    CHECK_GT(num_cuda_devices, 0) << "No CUDA devices available";
 
    int selected_gpu_index = -1;
    if (gpu_index >= 0) {
        selected_gpu_index = gpu_index;
    } else {
        std::vector<cudaDeviceProp> all_devices(num_cuda_devices);
        for (int device_id = 0; device_id < num_cuda_devices; ++device_id) {
            cudaGetDeviceProperties(&all_devices[device_id], device_id);
        }
        std::sort(all_devices.begin(), all_devices.end(), CompareCudaDevice);
        CUDA_SAFE_CALL(
                cudaChooseDevice(&selected_gpu_index, all_devices.data()));
        VLOG(2) << "Found " << num_cuda_devices << " CUDA device(s), "
                << "selected device " << selected_gpu_index << " with name "
                << all_devices[selected_gpu_index].name;
    }
 
    CHECK_GE(selected_gpu_index, 0);
    CHECK_LT(selected_gpu_index, num_cuda_devices)
            << "Invalid CUDA GPU selected";
 
    cudaDeviceProp device;
    cudaGetDeviceProperties(&device, selected_gpu_index);
    CUDA_SAFE_CALL(cudaSetDevice(selected_gpu_index));
}
 
}  // namespace colmap