#13639: Skylighting package compilation is glacial -------------------------------------+------------------------------------- Reporter: bgamari | Owner: dfeuer Type: bug | Status: new Priority: normal | Milestone: 8.4.1 Component: Compiler | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by niteria): This package has 123 modules which contain nothing else than a giant multi-kilobyte `String`. See https://hackage.haskell.org/package/skylighting-0.3.3.1/src/src/Skylighting/... for example. With `-g` (DWARF) on `ghc-8.0.2` it appears to lead to ~40m compile times. I have a strong suspicion that we end up generating debugging information for each of these `(:)` cells, which is bound to be slow with 4 million of these total and the nesting levels of 10k. I may be wrong because #11095 was supposed to improve it and I'm running with https://git.haskell.org/ghc.git/commitdiff/29122312cc7b8f9890eb53f92d76ecdd8... already. I will try to confirm if the problem persists on HEAD. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13639#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler