cudaMemcpyAsync是 CUDA Runtime API 中的一个函数,用于在主机(CPU)和设备(GPU)之间异步地复制数据。与同步的cudaMemcpy函数不同,cudaMemcpyAsync允许数据传输操作在后台进行,CPU 可以在数据传输期间继续执行其他操作,从而提高计算效率。 函数原型 cudaError_tcudaMemcpyAsync(void*
之后,返回到pStream中的流就 可以被当作流参数供cudaMemcpyAsync和其他异步CUDA的API来使用。在使用异步 CUDA函数时,它们可能会从先前启动的异步操作中返回错误代码。 当执行异步数据传输时,必须使用固定(或非分页的)主机内存。可以使用cudaMallocHost函数或cudaHostAlloc函数分配固定内存: cudaError t cudaMallocHost(...
对于cuSPARSE来说,如果使用了cudaMemcpy拷贝数据后,host会自动阻塞住,等待device的计算结果。但是如果cuSPARSE库被配置来使用CUDA steam和cudaMemcpyAsync,我们就需要多留一个心眼,使用确保正确的同步行为来获取device的计算结果。 最后一点比较新奇的是标量的使用,这里要使用标量的引用形式。如下代码中的beta变量: float beta...
{ cudaMemcpyAsync(h_a + i * n / nstreams, d_a + i * n / nstreams, nbytes / nstreams, cudaMemcpyDeviceToHost, streams[i]); } } cudaEventRecord(stop_event, 0); cudaEventSynchronize(stop_event); cudaEventElapsedTime(&elapsed_time, start_event, stop_event); printf("%d streams:\t...
_kernel << <blocks, threads,0,0>> >(d_a, value);cudaMemcpyAsync(a, d_a, nbytes, cudaMemcpyDeviceToHost,0);cudaEventRecord(stop,0);sdkStopTimer(&timer);// have CPU do some work while waiting for stage 1 to finishunsignedlongintcounter =0;while(cudaEventQuery(stop) == cudaError...
Would it also mean that a failed cudaMemcpyAsync might lead to a subsequent kernel execution (queued in the same stream) tripping over uninitialized memory (e.g. used to index an array)? I think that is possible. Did I mention I suggest rigorous, proper error checking? sergeev917: still ri...
We found out because we created a “fake” inference function, that recreates the same cuda launches that OpenCV+cuDNN are doing. Similar number of kernels (dummy kernels in this case) and same cudaMemsetAsync and cudaMemcpyAsync calls, with the same streams with the same...
1 if the device can concurrently copy memory between host and device while executing a kernel, or 0 if not; ‣ cudaDevAttrMultiProcessorCount: Number of multiprocessors on the device; ‣ cudaDevAttrKernelExecTimeout: 1 if there is a run time limit for kernels executed on the device, or...
cudaMemcpyAsync(a, d_a, nbytes, cudaMemcpyDeviceToHost, 0); cudaEventRecord(stop, 0); CUT_SAFE_CALL( cutStopTimer(timer) ); // have CPU do some work while waiting for stage 1 to finish CPU等待GPU执行的循环次数 也就是说CPU完成这些迭代过程所消耗的时间就是等待GPU完成工作的时间 ...
CUBLAS_STATUS_INTERNAL_ERROR An internal cuBLAS operation failed. This error is usually caused by a cudaMemcpyAsync() failure. To correct: check that the hardware, an appropriate version of the driver, and the cuBLAS library are correctly installed. Also, check that the memory passed as a para...