From: haskell-cafe-bounces@haskell.org [mailto:haskell-cafe-bounces@haskell.org] On Behalf Of Hugh Perkins
Not many replies on this thread? Am I so wrong that no-one's even telling me? I find it hard to believe that if there were obvious errors in the proposition that anyone would resist pointing them out to me ;-)
Well, I vaguely recall a study which analysed a number of programs and determined that there was not a lot of inherent parallelism in them, so the effort to automate parallelism wouldn't have much payoff. Wait a sec... This isn't it, but seems relevant: http://www.detreville.org/papers/Limits.pdf Here you go: http://citeseer.ist.psu.edu/tremblay95impact.html
So, that leaves a couple of possibilites: some people are agreeing, but see no point in saying; or noone cares, because we all only have 1 or 2 core machines.
Well, the Harris/Singh paper summarises the common problems: - not many programs are inherently parallel - parallelism must be quite coarse to offset overheads (which I think is the problem with expecting things like map and fold to parallelised automagically; they're just too small grained for it to be worthwhile) - lazy evaluation makes it harder Basically, it's harder than it sounds. This is where NDP looks good. Although you have to explicitly label parallel operations, you get to use your functional tools like map and fold, etc. Alistair ***************************************************************** Confidentiality Note: The information contained in this message, and any attachments, may contain confidential and/or privileged material. It is intended solely for the person(s) or entity to which it is addressed. Any review, retransmission, dissemination, or taking of any action in reliance upon this information by persons or entities other than the intended recipient(s) is prohibited. If you received this in error, please contact the sender and delete the material from any computer. *****************************************************************