CUDA

  • 这个地址的描述比较容易理解
  • 简单总结就是,一套硬件加速计算的SDK
  • 看介绍混淆了SM


    计算能力
  • 上图列出的计算能力实际上是GPU系统架构的版本号,下面结构中的major,minor有提到
/**
 * CUDA device properties
 */
struct __device_builtin__ cudaDeviceProp
{
    char         name[256];                  /**< ASCII string identifying device */
    cudaUUID_t   uuid;                       /**< 16-byte unique identifier */
    char         luid[8];                    /**< 8-byte locally unique identifier. Value is undefined on TCC and non-Windows platforms */
    unsigned int luidDeviceNodeMask;         /**< LUID device node mask. Value is undefined on TCC and non-Windows platforms */
    size_t       totalGlobalMem;             /**< Global memory available on device in bytes */
    size_t       sharedMemPerBlock;          /**< Shared memory available per block in bytes */
    int          regsPerBlock;               /**< 32-bit registers available per block */
    int          warpSize;                   /**< Warp size in threads */
    size_t       memPitch;                   /**< Maximum pitch in bytes allowed by memory copies */
    int          maxThreadsPerBlock;         /**< Maximum number of threads per block */
    int          maxThreadsDim[3];           /**< Maximum size of each dimension of a block */
    int          maxGridSize[3];             /**< Maximum size of each dimension of a grid */
    int          clockRate;                  /**< Clock frequency in kilohertz */
    size_t       totalConstMem;              /**< Constant memory available on device in bytes */
    int          major;                      /**< Major compute capability */
    int          minor;                      /**< Minor compute capability */
    size_t       textureAlignment;           /**< Alignment requirement for textures */
    size_t       texturePitchAlignment;      /**< Pitch alignment requirement for texture references bound to pitched memory */
    int          deviceOverlap;              /**< Device can concurrently copy memory and execute a kernel. Deprecated. Use instead asyncEngineCount. */
    int          multiProcessorCount;        /**< Number of multiprocessors on device */
    int          kernelExecTimeoutEnabled;   /**< Specified whether there is a run time limit on kernels */
    int          integrated;                 /**< Device is integrated as opposed to discrete */
    int          canMapHostMemory;           /**< Device can map host memory with cudaHostAlloc/cudaHostGetDevicePointer */
    int          computeMode;                /**< Compute mode (See ::cudaComputeMode) */
    int          maxTexture1D;               /**< Maximum 1D texture size */
    int          maxTexture1DMipmap;         /**< Maximum 1D mipmapped texture size */
    int          maxTexture1DLinear;         /**< Maximum size for 1D textures bound to linear memory */
    int          maxTexture2D[2];            /**< Maximum 2D texture dimensions */
    int          maxTexture2DMipmap[2];      /**< Maximum 2D mipmapped texture dimensions */
    int          maxTexture2DLinear[3];      /**< Maximum dimensions (width, height, pitch) for 2D textures bound to pitched memory */
    int          maxTexture2DGather[2];      /**< Maximum 2D texture dimensions if texture gather operations have to be performed */
    int          maxTexture3D[3];            /**< Maximum 3D texture dimensions */
    int          maxTexture3DAlt[3];         /**< Maximum alternate 3D texture dimensions */
    int          maxTextureCubemap;          /**< Maximum Cubemap texture dimensions */
    int          maxTexture1DLayered[2];     /**< Maximum 1D layered texture dimensions */
    int          maxTexture2DLayered[3];     /**< Maximum 2D layered texture dimensions */
    int          maxTextureCubemapLayered[2];/**< Maximum Cubemap layered texture dimensions */
    int          maxSurface1D;               /**< Maximum 1D surface size */
    int          maxSurface2D[2];            /**< Maximum 2D surface dimensions */
    int          maxSurface3D[3];            /**< Maximum 3D surface dimensions */
    int          maxSurface1DLayered[2];     /**< Maximum 1D layered surface dimensions */
    int          maxSurface2DLayered[3];     /**< Maximum 2D layered surface dimensions */
    int          maxSurfaceCubemap;          /**< Maximum Cubemap surface dimensions */
    int          maxSurfaceCubemapLayered[2];/**< Maximum Cubemap layered surface dimensions */
    size_t       surfaceAlignment;           /**< Alignment requirements for surfaces */
    int          concurrentKernels;          /**< Device can possibly execute multiple kernels concurrently */
    int          ECCEnabled;                 /**< Device has ECC support enabled */
    int          pciBusID;                   /**< PCI bus ID of the device */
    int          pciDeviceID;                /**< PCI device ID of the device */
    int          pciDomainID;                /**< PCI domain ID of the device */
    int          tccDriver;                  /**< 1 if device is a Tesla device using TCC driver, 0 otherwise */
    int          asyncEngineCount;           /**< Number of asynchronous engines */
    int          unifiedAddressing;          /**< Device shares a unified address space with the host */
    int          memoryClockRate;            /**< Peak memory clock frequency in kilohertz */
    int          memoryBusWidth;             /**< Global memory bus width in bits */
    int          l2CacheSize;                /**< Size of L2 cache in bytes */
    int          persistingL2CacheMaxSize;   /**< Device's maximum l2 persisting lines capacity setting in bytes */
    int          maxThreadsPerMultiProcessor;/**< Maximum resident threads per multiprocessor */
    int          streamPrioritiesSupported;  /**< Device supports stream priorities */
    int          globalL1CacheSupported;     /**< Device supports caching globals in L1 */
    int          localL1CacheSupported;      /**< Device supports caching locals in L1 */
    size_t       sharedMemPerMultiprocessor; /**< Shared memory available per multiprocessor in bytes */
    int          regsPerMultiprocessor;      /**< 32-bit registers available per multiprocessor */
    int          managedMemory;              /**< Device supports allocating managed memory on this system */
    int          isMultiGpuBoard;            /**< Device is on a multi-GPU board */
    int          multiGpuBoardGroupID;       /**< Unique identifier for a group of devices on the same multi-GPU board */
    int          hostNativeAtomicSupported;  /**< Link between the device and the host supports native atomic operations */
    int          singleToDoublePrecisionPerfRatio; /**< Ratio of single precision performance (in floating-point operations per second) to double precision performance */
    int          pageableMemoryAccess;       /**< Device supports coherently accessing pageable memory without calling cudaHostRegister on it */
    int          concurrentManagedAccess;    /**< Device can coherently access managed memory concurrently with the CPU */
    int          computePreemptionSupported; /**< Device supports Compute Preemption */
    int          canUseHostPointerForRegisteredMem; /**< Device can access host registered memory at the same virtual address as the CPU */
    int          cooperativeLaunch;          /**< Device supports launching cooperative kernels via ::cudaLaunchCooperativeKernel */
    int          cooperativeMultiDeviceLaunch; /**< Device can participate in cooperative kernels launched via ::cudaLaunchCooperativeKernelMultiDevice */
    size_t       sharedMemPerBlockOptin;     /**< Per device maximum shared memory per block usable by special opt in */
    int          pageableMemoryAccessUsesHostPageTables; /**< Device accesses pageable memory via the host's page tables */
    int          directManagedMemAccessFromHost; /**< Host can directly access managed memory on the device without migration. */
    int          maxBlocksPerMultiProcessor; /**< Maximum number of resident blocks per multiprocessor */
    int          accessPolicyMaxWindowSize;  /**< The maximum value of ::cudaAccessPolicyWindow::num_bytes. */
    size_t       reservedSharedMemPerBlock;  /**< Shared memory reserved by CUDA driver per block in bytes */
};
  • multiProcessorCount表示的是SM的数量
GeForce 940MX:
multiProcessorCount 3
sharedMemPerBlock 48k
maxThreadsPerBlock 1024
maxThreadsPerMultiProcessor 2048
  • GPU vs CPU,根据这里的评估大约可以提高50倍的计算效率

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