Execute at the same time? Why do you need that?

Even if you use any feature of parallel programming, execute both at the same time can be hard to do it. If I'm not wrong, it will be impossible if you try to do it in a computer with a single processor/single thread, for example.

If you just want to make them run in parallel in the sense you want to start one and do not wait for it to finish to launch the second sub, you can use fork or threads. The best one depends on the OS you're running your program.

Check for Parallel::Fork module in CPAN. You should take a look at POE too, but the learning curve is longer then Parallel::Fork.