cuda 配置共享内存Bank模式API

拼搏现实的明天。 2022-11-21 14:54 168阅读 0赞

GPU共享内存Bank 4Byte or 8Byte模式查询和修改的cuda API。

### Access Mode Configuration ###

默认情况是4-byte模式，可以用下面的API来查看：

cudaError_t cudaDeviceGetSharedMemConfig(cudaSharedMemConfig *pConfig);

返回结果放在pConfig中，其结果可以是下面两种：

cudaSharedMemBankSizeFourByte
    
    cudaSharedMemBankSizeEightByte

可以使用下面的API来设置bank的大小：

cudaError_t cudaDeviceSetSharedMemConfig(cudaSharedMemConfig config);

bank的配置参数如下三种：

cudaSharedMemBankSizeDefault
    
    cudaSharedMemBankSizeFourByte
    
    cudaSharedMemBankSizeEightByte

cuda头文件中的API说明

/** * \brief Sets the shared memory configuration for the current device. * * On devices with configurable shared memory banks, this function will set * the shared memory bank size which is used for all subsequent kernel launches. * Any per-function setting of shared memory set via ::cudaFuncSetSharedMemConfig * will override the device wide setting. * * Changing the shared memory configuration between launches may introduce * a device side synchronization point. * * Changing the shared memory bank size will not increase shared memory usage * or affect occupancy of kernels, but may have major effects on performance. * Larger bank sizes will allow for greater potential bandwidth to shared memory, * but will change what kinds of accesses to shared memory will result in bank * conflicts. * * This function will do nothing on devices with fixed shared memory bank size. * * The supported bank configurations are: * - ::cudaSharedMemBankSizeDefault: set bank width the device default (currently, * four bytes) * - ::cudaSharedMemBankSizeFourByte: set shared memory bank width to be four bytes * natively. * - ::cudaSharedMemBankSizeEightByte: set shared memory bank width to be eight * bytes natively. * * \param config - Requested cache configuration * * \return * ::cudaSuccess, * ::cudaErrorInvalidValue * \notefnerr * \note_init_rt * \note_callback * * \sa ::cudaDeviceSetCacheConfig, * ::cudaDeviceGetCacheConfig, * ::cudaDeviceGetSharedMemConfig, * ::cudaFuncSetCacheConfig, * ::cuCtxSetSharedMemConfig */

在头文件的函数说明中有一点要注意，其启动不同的kernel之间修改bank配置会有一个**隐式的device同步点**。

* Changing the shared memory configuration between launches may introduce
     * a device side synchronization point.