Yes. But immutability is not the whole job. You have to make sure to use the right data structures. Linear data structures like lists don't parallelize well. You need to use something that breaks into more equal parts instead of car and cdr.
Compare Guy Steele's talk "Get rid of Cons" at the International Conference on Functional Programming 2009. For the slides go to http://news.ycombinator.com/item?id=814632, the video should also be available online somewhere.
Compare Guy Steele's talk "Get rid of Cons" at the International Conference on Functional Programming 2009. For the slides go to http://news.ycombinator.com/item?id=814632, the video should also be available online somewhere.