Initalization and Information


Returns the number of installed CUDA-enabled devices.

C++: int cuda::getCudaEnabledDeviceCount()

Use this function before any other CUDA functions calls. If OpenCV is compiled without CUDA support, this function returns 0.


Sets a device and initializes it for the current thread.

C++: void cuda::setDevice(int device)
  • device – System index of a CUDA device starting with 0.

If the call of this function is omitted, a default device is initialized at the fist CUDA usage.


Returns the current device index set by cuda::setDevice() or initialized by default.

C++: int cuda::getDevice()


Explicitly destroys and cleans up all resources associated with the current device in the current process.

C++: void cuda::resetDevice()

Any subsequent API call to this device will reinitialize the device.


Enumeration providing CUDA computing features.

C++: enum cuda::FeatureSet


class cuda::TargetArchs

Class providing a set of static methods to check what NVIDIA* card architecture the CUDA module was built for.

The following method checks whether the module was built with the support of the given feature:

C++: static bool cuda::TargetArchs::builtWith(FeatureSet feature_set)

There is a set of methods to check whether the module contains intermediate (PTX) or binary CUDA code for the given architecture(s):

C++: static bool cuda::TargetArchs::has(int major, int minor)
C++: static bool cuda::TargetArchs::hasPtx(int major, int minor)
C++: static bool cuda::TargetArchs::hasBin(int major, int minor)
C++: static bool cuda::TargetArchs::hasEqualOrLessPtx(int major, int minor)
C++: static bool cuda::TargetArchs::hasEqualOrGreater(int major, int minor)
C++: static bool cuda::TargetArchs::hasEqualOrGreaterPtx(int major, int minor)
C++: static bool cuda::TargetArchs::hasEqualOrGreaterBin(int major, int minor)
  • major – Major compute capability version.
  • minor – Minor compute capability version.

According to the CUDA C Programming Guide Version 3.2: “PTX code produced for some specific compute capability can always be compiled to binary code of greater or equal compute capability”.


class cuda::DeviceInfo

Class providing functionality for querying the specified GPU properties.

class CV_EXPORTS DeviceInfo
    //! creates DeviceInfo object for the current GPU

    //! creates DeviceInfo object for the given GPU
    DeviceInfo(int device_id);

    //! ASCII string identifying device
    const char* name() const;

    //! global memory available on device in bytes
    size_t totalGlobalMem() const;

    //! shared memory available per block in bytes
    size_t sharedMemPerBlock() const;

    //! 32-bit registers available per block
    int regsPerBlock() const;

    //! warp size in threads
    int warpSize() const;

    //! maximum pitch in bytes allowed by memory copies
    size_t memPitch() const;

    //! maximum number of threads per block
    int maxThreadsPerBlock() const;

    //! maximum size of each dimension of a block
    Vec3i maxThreadsDim() const;

    //! maximum size of each dimension of a grid
    Vec3i maxGridSize() const;

    //! clock frequency in kilohertz
    int clockRate() const;

    //! constant memory available on device in bytes
    size_t totalConstMem() const;

    //! major compute capability
    int majorVersion() const;

    //! minor compute capability
    int minorVersion() const;

    //! alignment requirement for textures
    size_t textureAlignment() const;

    //! pitch alignment requirement for texture references bound to pitched memory
    size_t texturePitchAlignment() const;

    //! number of multiprocessors on device
    int multiProcessorCount() const;

    //! specified whether there is a run time limit on kernels
    bool kernelExecTimeoutEnabled() const;

    //! device is integrated as opposed to discrete
    bool integrated() const;

    //! device can map host memory with cudaHostAlloc/cudaHostGetDevicePointer
    bool canMapHostMemory() const;

    enum ComputeMode
        ComputeModeDefault,         /**< default compute mode (Multiple threads can use ::cudaSetDevice() with this device) */
        ComputeModeExclusive,       /**< compute-exclusive-thread mode (Only one thread in one process will be able to use ::cudaSetDevice() with this device) */
        ComputeModeProhibited,      /**< compute-prohibited mode (No threads can use ::cudaSetDevice() with this device) */
        ComputeModeExclusiveProcess /**< compute-exclusive-process mode (Many threads in one process will be able to use ::cudaSetDevice() with this device) */

    //! compute mode
    ComputeMode computeMode() const;

    //! maximum 1D texture size
    int maxTexture1D() const;

    //! maximum 1D mipmapped texture size
    int maxTexture1DMipmap() const;

    //! maximum size for 1D textures bound to linear memory
    int maxTexture1DLinear() const;

    //! maximum 2D texture dimensions
    Vec2i maxTexture2D() const;

    //! maximum 2D mipmapped texture dimensions
    Vec2i maxTexture2DMipmap() const;

    //! maximum dimensions (width, height, pitch) for 2D textures bound to pitched memory
    Vec3i maxTexture2DLinear() const;

    //! maximum 2D texture dimensions if texture gather operations have to be performed
    Vec2i maxTexture2DGather() const;

    //! maximum 3D texture dimensions
    Vec3i maxTexture3D() const;

    //! maximum Cubemap texture dimensions
    int maxTextureCubemap() const;

    //! maximum 1D layered texture dimensions
    Vec2i maxTexture1DLayered() const;

    //! maximum 2D layered texture dimensions
    Vec3i maxTexture2DLayered() const;

    //! maximum Cubemap layered texture dimensions
    Vec2i maxTextureCubemapLayered() const;

    //! maximum 1D surface size
    int maxSurface1D() const;

    //! maximum 2D surface dimensions
    Vec2i maxSurface2D() const;

    //! maximum 3D surface dimensions
    Vec3i maxSurface3D() const;

    //! maximum 1D layered surface dimensions
    Vec2i maxSurface1DLayered() const;

    //! maximum 2D layered surface dimensions
    Vec3i maxSurface2DLayered() const;

    //! maximum Cubemap surface dimensions
    int maxSurfaceCubemap() const;

    //! maximum Cubemap layered surface dimensions
    Vec2i maxSurfaceCubemapLayered() const;

    //! alignment requirements for surfaces
    size_t surfaceAlignment() const;

    //! device can possibly execute multiple kernels concurrently
    bool concurrentKernels() const;

    //! device has ECC support enabled
    bool ECCEnabled() const;

    //! PCI bus ID of the device
    int pciBusID() const;

    //! PCI device ID of the device
    int pciDeviceID() const;

    //! PCI domain ID of the device
    int pciDomainID() const;

    //! true if device is a Tesla device using TCC driver, false otherwise
    bool tccDriver() const;

    //! number of asynchronous engines
    int asyncEngineCount() const;

    //! device shares a unified address space with the host
    bool unifiedAddressing() const;

    //! peak memory clock frequency in kilohertz
    int memoryClockRate() const;

    //! global memory bus width in bits
    int memoryBusWidth() const;

    //! size of L2 cache in bytes
    int l2CacheSize() const;

    //! maximum resident threads per multiprocessor
    int maxThreadsPerMultiProcessor() const;

    //! gets free and total device memory
    void queryMemory(size_t& totalMemory, size_t& freeMemory) const;
    size_t freeMemory() const;
    size_t totalMemory() const;

    //! checks whether device supports the given feature
    bool supports(FeatureSet feature_set) const;

    //! checks whether the CUDA module can be run on the given device
    bool isCompatible() const;


The constructors.

C++: cuda::DeviceInfo::DeviceInfo()
C++: cuda::DeviceInfo::DeviceInfo(int device_id)
  • device_id – System index of the CUDA device starting with 0.

Constructs the DeviceInfo object for the specified device. If device_id parameter is missed, it constructs an object for the current device.


Returns the device name.

C++: const char* cuda::DeviceInfo::name() const


Returns the major compute capability version.

C++: int cuda::DeviceInfo::majorVersion()


Returns the minor compute capability version.

C++: int cuda::DeviceInfo::minorVersion()


Returns the amount of free memory in bytes.

C++: size_t cuda::DeviceInfo::freeMemory()


Returns the amount of total memory in bytes.

C++: size_t cuda::DeviceInfo::totalMemory()


Provides information on CUDA feature support.

C++: bool cuda::DeviceInfo::supports(FeatureSet feature_set) const

This function returns true if the device has the specified CUDA feature. Otherwise, it returns false .


Checks the CUDA module and device compatibility.

C++: bool cuda::DeviceInfo::isCompatible()

This function returns true if the CUDA module can be run on the specified device. Otherwise, it returns false .


Returns system index of the CUDA device starting with 0.

C++: int cuda::DeviceInfo::deviceID()