first function unknown

Question

I am doing first steps with KCachegrind/Cachegrind. I run Cachegrind on machine A then I moved the output files on machine B where I have KCachegrind installed.

I don't know why but I have always first function displayed as (unknown) and it is bad because I have there the 19.46 of the usage as displayed in the picture. What I am doing wrong? Is the output file supposed to have all necessary information?

1. I am using compilation flag -g is it enough? I would like to use the ptimized version by the way but I don't know if it works.
2. Could it be that it is best if I run Kcachegrind on the same machine where I do my profiling?

Answer 1

I would check when this 'unknown' function is called in the lifetime of you program. If the unknown function is called before main then its not your code and you shouldn't really worry about it. If its after main then it still might not be your code, but will take some more investigating.