定时 CUDA 操作 [英] Timing CUDA operations

问题描述

我需要为 CUDA 内核执行计时.最佳实践指南说我们可以在 Windows 中使用事件或标准计时函数，如 clock().我的问题是使用这两个函数会给我一个完全不同的结果.事实上，事件给出的结果与实践中的实际速度相比，似乎是巨大的.

I need to time a CUDA kernel execution. The Best Practices Guide says that we can use either events or standard timing functions like clock() in Windows. My problem is that using these two functions gives me a totally different result. In fact, the result given by events seems to be huge compared to the actual speed in practice.

我真正需要的是能够通过首先在较小的数据集上运行计算的简化版本来预测计算的运行时间.不幸的是，这个基准测试的结果完全不切实际，要么过于乐观(clock())，要么过于悲观(事件).

What I actually need all this for is to be able to predict the running time of a computation by first running a reduced version of it on a smaller data set. Unfortunately, the results of this benchmark are totally unrealistic, being either too optimistic (clock()) or waaaay too pessimistic (events).

推荐答案

你可以这样做:

#include <sys/time.h>

struct timeval t1, t2;

gettimeofday(&t1, 0);

kernel_call<<<dimGrid, dimBlock, 0>>>();

HANDLE_ERROR(cudaThreadSynchronize();)

gettimeofday(&t2, 0);

double time = (1000000.0*(t2.tv_sec-t1.tv_sec) + t2.tv_usec-t1.tv_usec)/1000.0;

printf("Time to generate:  %3.1f ms 
", time);

或:

float time;
cudaEvent_t start, stop;

HANDLE_ERROR( cudaEventCreate(&start) );
HANDLE_ERROR( cudaEventCreate(&stop) );
HANDLE_ERROR( cudaEventRecord(start, 0) );

kernel_call<<<dimGrid, dimBlock, 0>>>();

HANDLE_ERROR( cudaEventRecord(stop, 0) );
HANDLE_ERROR( cudaEventSynchronize(stop) );
HANDLE_ERROR( cudaEventElapsedTime(&time, start, stop) );

printf("Time to generate:  %3.1f ms 
", time);

这篇关于定时 CUDA 操作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！