I'll hazard a guess that XML::Simple is reading the whole file, parsing it, creating a data structure and only then returning. That's always going to take time, and for a large document it'll produce a *huge* data structure which might even make your machine swap - hence the sloooooowness.

You might want to look at a streaming parser instead, which reads the file a bit at a time, generating a series of events for you to handle. It'll be a bit more work but will save an awful lot of memory. Even if it's not any faster over all, it'll at least start giving you data sooner so will *appear* to be faster!