On Tue, Oct 25, 2011 at 1:24 PM, Ketil Malde <ketil@malde.org> wrote:

You must be a lot more confident than I if you say this without
benchmarking first. :-) IME, there are (at least) two possible problems
here, 1) transactions scale (quadratically, I think) with the number of
TVars touched, so if any transaction touch a large part of the array,
it's going to cost you, [...]

That woud remain true no matter what, but the current quadratic behaviour is I believe easily enough fixed by switching to a better data structure than a list.