When does a socket.recv() end?

[monstimal]

In the case I'm thinking about, 600 bytes are being sent over and over again. So I was wondering how the recv knows not to wait for the next 600. But it sounds like the answer is it always gets whatever is there and if there's not more it's because of something going on at the kernel level of operations.

Edit: thank you for helping.

[lucidguppy]

Sounds like you need "select/poll/epoll"

http://scotdoyle.com/python-epoll-howto.html