[fulafel]

Generally yes to the first question, no to the second.

If you want your code to have low perturbance on other concurrent work done by the system, implementing it in a inefficient way doesn't usually help with that goal, since then your code will just be executing all the time because it takes a long time to finish. And you still won't have good control of the execution resources compared to using normal tools like OS scheduling policies to address the goal.