[Moving to GHC users list] There are several things that aren't research issues: notably, faster copying, fewer intermediate lists, fewer state-monad-induced intermediate closures. These are things that would move sharply up our priority list if you had a real application that was stumbling on them. What I obviously can't promise is that improving these things would solve your problem -- if, indeed, you turn out to have one! Simon | -----Original Message----- | From: S. Alexander Jacobson [mailto:alex@i2x.com] | Sent: 26 February 2004 23:27 | To: Simon Peyton-Jones | Cc: haskell@haskell.org | Subject: RE: [Haskell] performance tuning Data.FiniteMap | | Is fixing GHC arrays a big research job or is it | something that someone can straightforwardly | handle if my site actually gets enough traffic to | warrant it? | | -Alex- | | On Thu, 26 Feb 2004, Simon Peyton-Jones wrote: | | > | But in managing this tradeoff, what is faster: | > | * constructing/destructing e.g. 16 trees (for a 65000 item table) | > | * 2 memcpy of 256 item arrays (perhaps after you primop?) | > | | > | If the later is not dramatically slower than I | > | will bias towards more arrayness. | > | > I doubt the latter is dramatically slower, but you'd have to experiment | > to find out. And GHC is not doing as well as it should on arrays just | > now. (One of the things on our to-do list.) Might vary between | > implementations too. | > | > Simon | > | | _________________________________________________________________ | S. Alexander Jacobson mailto:me@alexjacobson.com | tel:917-770-6565 http://alexjacobson.com