What is the relationship between task priority and thread priority? If I "renice" an app from terminal, is the new priority inherited by all the threads in a multi-threaded task? Is the behavior the same for pthreads and NSThreads? (I would assume so, since the latter is based on the former.) Is niceness entirely transparent to the app? And if I set the priority of a given thread in code, how does that relate to the task priority if that gets reniced?