| First bad thing: | Stack size (memory consumed) doubles each time it overflows. | | Second bad thing: | Arbitrary limit on stack size unrelated to overall (heap) memory | available. | | Third bad thing (the really bad thing): | If a stack has temporarily grown (to 64M say), it will never shrink | back down again to something more typical (< 4K say). If I understand | correctly, it will continue to take 64M from the heap regardless. | | What I would like is to be able to set an upper limit on total memory | useage and allow the program to freely use this memory as either stack | or heap. At least that should be the default behaviour, but maybe | also allow +RTS restrictions for "debugging" (though I don't think this | is a very good way of investigating a programs stack use). | | I would also like stack memory allocation to increase (and decrease :-) | in some sane sized linear increment, not double each time. With the | current scheme, as I understand it, if 65M is needed then 128M will be | allocated.
Would you like to create a ticket for this? I don't know how many people it bites, and how often, but it'd be good to have it recorded. Changing to a linear increment would be relatively straightforward, but would have quadratic copying cost as the stack grew big. Shrinking stacks would not be hard, I think, at the cost of perhaps copying them again if they grew big. | Stefan O'Rear suggested an alternative. I don't know how hard it would | be to implement though (don't really know anything about ghc rts). | | http://haskell.org/pipermail/glasgow-haskell-users/2007-May/012472.html Yes, this is the standard solution, and it's a good one because it has a robust cost model (no quadratic costs). However, it's tricky to get right; copying is simpler. If a significant fraction of runtime (for some interesting program(s)) turned out to be consumed by copying stacks then we could consider this. Simon _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
