I will probably need this so …

Ivan's blog

This post will show you some points about how to measure time in Cuda.

Reading the documentation about Cuda you could find two ways:

  • cutStartTimer(myTimer)
  • Events

Events are a bit more sophisticated and, if your code uses asynchronous kernels, you must to use it. But, how could you know if a code has an asynchronous kernel or not?

To let a code be asynchronous the programmer must create streams with the input data and transfers it to the device using the instruction:


In conclusion, if in the code there is not any instruction like ‘cudaStreamCreate’ and ‘cudaMemcpyAsync’ you cold assume that your code is synchronous (simplifying the measurements).

Measuring with the cut{Start|Stop}Timer

It is very important to use the instruction cudaThreadSynchronize() to avoid erroneous measurements.

The code is bellow:

The output:

[ivan@machine]$ ./timer Device name : Tesla C2050 Time for selecting the device: 3423.731934 ms Time for the kernel: 0.068000…

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