yangyi0239

question about timing in brook and cal

Discussion created by yangyi0239 on Mar 27, 2009
Latest reply on Mar 30, 2009 by yangyi0239

Currently I'm working on cal and brook. Sometimes I implemented applications in cal and brook. And I notices that the timing information show the brook is faster than cal. For example, if we run the optimized matmult from brook samples and the compute_matmult from the cal sample. The result is follow:

result from brook:

Width  Height      Iterations  CPU Total Time  GPU Total Time          Gflops         Speedup
 1024    1024               1         32.7529        0.127423         15.6957         257.041

 

result from cal:

Matrix Size     Kernel Gflops  System Gflops    Kernel Time     System Time
(1024x1024)     287.212         11.059          0.0075          0.1942

 

Compared to 0.1942 from cal, the brook 0.127423 is really fast. On the other hand, the kernel gflops of cal is really high. I believe something is wrong with the timing. Can anyone explain it?

 

 

If I changed the iteration to 16

brook:

   Width  Height      Iterations  CPU Total Time  GPU Total Time          Gflops         Speedup
    1024    1024              16         536.969        0.556496         57.5026         964.911

 

cal:

Matrix Size     Kernel Gflops  System Gflops    Kernel Time     System Time
(1024x1024)     393.469         11.914          0.0873          2.8841

Outcomes