If you are using the VMWare Perl SDK, you need to avoid using the find_entity_views unless you also call it with a property filter, such as properties => ['vm', 'summary']. This keeps the API from gathering all the available information about each node it traverses. There is a lot of data, and some of it (like performance counters) are generated each time they are asked for. This makes runtime operations very slow. My script to parse VMWare info went from an 8 minute run to less then 20 seconds after properly filtering down the property list.