Just a couple of things I was wondering about... 1. Is there some way to assign a "priority" to Haskell threads? (The behaviour I'd like is that high priority threads always run first, and low priority threads potentially never run at all unless there's an available processor which is completely idle.) 2. I have a situation where I have a thread generating some data and putting it into a mutable array, and another thread trying to read that data. Is there a way I can make the reader thread block if it tries to read a cell that hasn't been computed yet, but not introduce too much overhead for cells that have been filled in? 3. Would it be hard to make it so that the number of real threads (the RTS +N flag) could be adjusted at runtime?