#427: Random.StdGen slowness --------------------------------------+------------------------------------- Reporter: remit | Owner: rrnewton Type: bug | Status: new Priority: normal | Milestone: _|_ Component: libraries/random | Version: Resolution: None | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: Runtime performance bug | Difficulty: Unknown Testcase: | Blockedby: Blocking: | Related: --------------------------------------+------------------------------------- Comment(by joell): This ticket seems to be almost describing two separate issues: the performance of the random package and the "thunk-bomb" problem in `getStdRandom`. While I admit I haven't looked into the performance aspect, I am now well acquainted with the "thunk-bomb" aspect. Turns out a metrics library we were using at my company made a `randomRIO` call that in some cases (all of them in our configuration) wouldn't actually use the generated random value. This led to me spending a few days trying to figure out why our services were consuming and retaining gigabytes of memory. (For those interested in case studies, the discussion with the metrics library folks is here: https://github.com/brendanhay/network-metrics/issues/4 .) So I would like to petition that the change Remi suggested in comment:17 to make `getStdRandom` strict (or something along those lines) be made. To my mind (heavily biased by the experience of the last few days), I wouldn't really consider the "thunk-bomb" aspect a performance problem so much as a stability one. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/427#comment:20 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler