I'm working on a game sort of thing where users can write arbitrary code for individual agents, and I'm trying to decide the best way to divide up computation time.

The simplest option would be to give each agent a set amount of time and skip their turn if it elapses without an action being decided upon, but I would like people to be able to write their agents decision functions without having to think too much about how long its taking unless they really want to.

The two approaches I'm considering are giving each agent a set number of bytecode instructions (taking cost into account) each timestep, and making players deal with the consequences of the game state changing between blocks of computation (as with Battlecode) or giving each agent it's own thread and giving each thread equal time on the processor.

I'm about equally knowledgeable on both concurrency and bytecode stuff, which is to say not very, so I'm wondering which approach would be best. I have a clearer idea of how I'd structure things if I used bytecode, but less certainty about how to actually implement the analysis. I'm pretty sure I can work up a concurrency based system without much trouble, but I worry it will be messier with more overhead and will add unnecessary complexity to the project.