The first thing I notice is that you are starting your finisher thread inside your for ever loop. That means you will start a new finisher every time you loop and never clean up the old ones.

The second thing is that your finisher thread is in a tight loop. (while(1)). That's bad. It means that thread will consume as much cpu as the scheduler gives it, to the detriment of every other thread (and process) in the system.

Move the creation of that thread outside (above) the for loop and add a short (0.1) delay and the overall responsiveness of your program (and entire system) will improve.

Finally, and most importantly, you are joining these threads, but then doing nothing at all with the results. Indeed, you aren't returning anything in the first place. So why bother to join them? Are you intending doing something useful at a later point?