It’s generally worth installing one of the math modules for
Math::BigInt to use early on after installing perl if you want to ensure your installs (and your perl in general) goes as quickly as possible. Some of the crypto and random number modules use
Math::BigInt and without a fast module under the hood they can take quite a long time to do anything.
If you use cpanm to install them use verbose mode (-v) because it’s quite likely they will either ask for input or fail the first time as they check for dependencies.
cpanm -v Math::BigInt::GMP cpanm -v Math::BigInt::Pari
There may be good reasons to choose one module over the other but I don’t know what they are are. I just went with the one that installed easily. It makes quite a noticeable difference to installing certain modules like Crypt::DH. In fact you can see the time it takes without a fast library in the bug reports against it.