1/* This sample demonstrates the way you can perform independed tasks
2   on the different GPUs */
3
4// Disable some warnings which are caused with CUDA headers
5#if defined(_MSC_VER)
6#pragma warning(disable: 4201 4408 4100)
7#endif
8
9#include <iostream>
10#include "cvconfig.h"
11#include "opencv2/core/core.hpp"
12#include "opencv2/cudaarithm.hpp"
13
14#ifdef HAVE_TBB
15#  include "tbb/tbb_stddef.h"
16#  if TBB_VERSION_MAJOR*100 + TBB_VERSION_MINOR >= 202
17#    include "tbb/tbb.h"
18#    include "tbb/task.h"
19#    undef min
20#    undef max
21#  else
22#    undef HAVE_TBB
23#  endif
24#endif
25
26#if !defined(HAVE_CUDA) || !defined(HAVE_TBB) || defined(__arm__)
27
28int main()
29{
30#if !defined(HAVE_CUDA)
31    std::cout << "CUDA support is required (CMake key 'WITH_CUDA' must be true).\n";
32#endif
33
34#if !defined(HAVE_TBB)
35    std::cout << "TBB support is required (CMake key 'WITH_TBB' must be true).\n";
36#endif
37
38#if defined(__arm__)
39    std::cout << "Unsupported for ARM CUDA library." << std::endl;
40#endif
41
42    return 0;
43}
44
45#else
46
47#include <cuda.h>
48#include <cuda_runtime.h>
49
50using namespace std;
51using namespace cv;
52using namespace cv::cuda;
53
54struct Worker { void operator()(int device_id) const; };
55void destroyContexts();
56
57#define safeCall(expr) safeCall_(expr, #expr, __FILE__, __LINE__)
58inline void safeCall_(int code, const char* expr, const char* file, int line)
59{
60    if (code != CUDA_SUCCESS)
61    {
62        std::cout << "CUDA driver API error: code " << code << ", expr " << expr
63            << ", file " << file << ", line " << line << endl;
64        destroyContexts();
65        exit(-1);
66    }
67}
68
69// Each GPU is associated with its own context
70CUcontext contexts[2];
71
72int main()
73{
74    int num_devices = getCudaEnabledDeviceCount();
75    if (num_devices < 2)
76    {
77        std::cout << "Two or more GPUs are required\n";
78        return -1;
79    }
80
81    for (int i = 0; i < num_devices; ++i)
82    {
83        cv::cuda::printShortCudaDeviceInfo(i);
84
85        DeviceInfo dev_info(i);
86        if (!dev_info.isCompatible())
87        {
88            std::cout << "CUDA module isn't built for GPU #" << i << " ("
89                 << dev_info.name() << ", CC " << dev_info.majorVersion()
90                 << dev_info.minorVersion() << "\n";
91            return -1;
92        }
93    }
94
95    // Init CUDA Driver API
96    safeCall(cuInit(0));
97
98    // Create context for GPU #0
99    CUdevice device;
100    safeCall(cuDeviceGet(&device, 0));
101    safeCall(cuCtxCreate(&contexts[0], 0, device));
102
103    CUcontext prev_context;
104    safeCall(cuCtxPopCurrent(&prev_context));
105
106    // Create context for GPU #1
107    safeCall(cuDeviceGet(&device, 1));
108    safeCall(cuCtxCreate(&contexts[1], 0, device));
109
110    safeCall(cuCtxPopCurrent(&prev_context));
111
112    // Execute calculation in two threads using two GPUs
113    int devices[] = {0, 1};
114    tbb::parallel_do(devices, devices + 2, Worker());
115
116    destroyContexts();
117    return 0;
118}
119
120
121void Worker::operator()(int device_id) const
122{
123    // Set the proper context
124    safeCall(cuCtxPushCurrent(contexts[device_id]));
125
126    Mat src(1000, 1000, CV_32F);
127    Mat dst;
128
129    RNG rng(0);
130    rng.fill(src, RNG::UNIFORM, 0, 1);
131
132    // CPU works
133    cv::transpose(src, dst);
134
135    // GPU works
136    GpuMat d_src(src);
137    GpuMat d_dst;
138    cuda::transpose(d_src, d_dst);
139
140    // Check results
141    bool passed = cv::norm(dst - Mat(d_dst), NORM_INF) < 1e-3;
142    std::cout << "GPU #" << device_id << " (" << DeviceInfo().name() << "): "
143        << (passed ? "passed" : "FAILED") << endl;
144
145    // Deallocate data here, otherwise deallocation will be performed
146    // after context is extracted from the stack
147    d_src.release();
148    d_dst.release();
149
150    CUcontext prev_context;
151    safeCall(cuCtxPopCurrent(&prev_context));
152}
153
154
155void destroyContexts()
156{
157    safeCall(cuCtxDestroy(contexts[0]));
158    safeCall(cuCtxDestroy(contexts[1]));
159}
160
161#endif
162