If you are so concerned about speed why are you still using Tie::File ? Most answers to Improving dismal performance - Part 1 suggested dropping that module and using simple open and <> for reading and writing.

That the total elapsed time is higher than your user+system time could have different reasons (I'm guessing since I haven't used dprof):

1. Other programs on your system might produce load that is counted in the total time

2. Accessing the hard disc produces waits (because the disc is slow compared to the processor) which is not counted in system time. While your program waits for the I/O other programs get to run or if all other programs wait the CPU goes into a sleep state

3. You could be on a double-core system and maybe dprof produces wrong output in this case. In the other thread tim.bunce said dprof was broken, maybe this is one of the parts that is broken.

I would say that 2. is the most likely answer.

The %Time percentages of more than 100% might be because of imprecisions in the time measurements or because of broken dprof on a double-core system. Or simply because dprof is broken (I'll just assume tim.bunces word as fact here).