Does the Visual Profiler

Hello everyone,I have some questions about visual profiler to ask,I want to know whether anybody had encountered these problems or someone knows what’s going on.

I was using visual profiler to measure the ratio of compute time to memcpy time. The program execution time is very long, it’s about 1 hour when measuring with “gettimeofday”. The strange thing is that the “session value” is just 75.353s, although I was waiting the visual profiler result about 1 hour.

The questions are:
(1) Does the session value means the total program execution time?
(2) Does the Visual Profiler not always accurate so that it could cause a big difference between measured time and actual time?
(3) Does it ordinary that the avg. throughput of memcpy is a negative value? Or it just caused by a mistake?
(4) Does the “Compute/Memcpy” value reflects the actual ratio of compute time to memcpy time?

Thanks so much!

I’m first time to post on here, so I forgot to enter the whole title of this post, and I don’t know how to change it.