Profiler Kernel Speeds faster than cmd?

Accelerated Computing CUDA CUDA Programming and Performance
1

I have noticed that when I run my code in a command line it takes ~5.5 ms but when I run it using the CUDA profiler it only takes ~3.25 ms. Has anybody else noticed this? Is the profiler maybe passing some argument that optimizes the GPU usage?

I really have no clue on why this would be, but I thought I would ask.

Thanks!

2

well, how did you measure?

3

I used :

CUT_SAFE_CALL(cutCreateTimer(&timer_tot));

    CUT_SAFE_CALL(cutStartTimer(timer_tot));

with the appropriate timer stop functions and do a printf to the screen with the number of milliseconds taken. This displays the time in the cmd window and in a little display box in the profiler.

4

I think there are 2 possibilities:

  • The profiler already initializes the card
  • The profiler runs your code more than once and you see the second/third where the card is already initialized
5

My timer does not include the initialization, just the memory transfers and kernel execution.

Could somebody else try running their own code and see if they have the same trend?