I wonder how to make a status checker, checking about 500 addresses in a few minutes? (it\'ll check a certain port if its listening).
But I care about the performanc
They keyword in this is non-blocking. You would want to have a certain callback when an attempt is succesful and be able to run more calls in the meantime.
Some functions like sockets from DaveRandom's answer allow for a non-blocking mode to do this in regular php installations. You can also use different programming languages such as node.js to do this very efficiently because they are designed to be non-blocking.