C4::Biblio::GetAuthorisedValueDesc() is used in many places. In C4::XSLT::transformMARCXML4XSLT() for example it will convert all subfields defined with an authorised value category. For better performance, add cache to this function. It will improve a lot when there are a lot of items with same value in branch, location, ccode, ...
Forget about it, found Bug 28371 *** This bug has been marked as a duplicate of bug 28371 ***