#200: Allow more convenient use of ghc profiling options -auto and -auto-all ----------------------------+----------------------------------------------- Reporter: guest | Owner: Type: enhancement | Status: new Priority: normal | Milestone: Cabal-1.6 Component: Cabal library | Version: Severity: normal | Resolution: Keywords: | Difficulty: easy (<4 hours) Ghcversion: 6.8.2 | Platform: ----------------------------+----------------------------------------------- Comment (by dolio): It may be that having annotations on all the libraries one uses is too much information. However, I'd argue that annotations on library calls isn't useful merely for profiling said libraries. So, my program is slow, and it spends most of the time in function f. f x = ... includes calls to some libraries ... What is slow about f? Is it doing some of its own stuff that takes time/memory, or if we unfolded one level, would we find that 90% of f's work is done in the library calls it makes? Now, at some level, I suppose you can get carried away with that (f doesn't do any work, it's all GHC primops :)), but I think that a bit of such information can be useful, to tell me that I need to swap in a different data structure, or contact the library's maintainer and see if anything can be done to speed it up. Maybe you can do some of that with manual SCC annotations, but I've had trouble getting those to work well for me. At least, it seems to me that there are situations where libraries aren't simply a profiling black hole would be useful when *not* profiling that particular library (even if only to tell you that that library needs to be profiled :)). See the somewhat recent BLAS optimization question on haskell-cafe for a potential example (is it his use of lists and non-fused operations? Is BLAS itself slow? etc.). It'd be nice if there were a way to turn -auto-all on and off for libraries when compiling an application that uses those libraries. Of course, I don't suspect that's an option at the moment (I suppose you could build two sets of profiling files for each library, and have some way of selecting them, but I imagine that'd be hairy). Anyhow, just my 2 cents on the issue. -- Ticket URL: http://hackage.haskell.org/trac/hackage/ticket/200#comment:8 Hackage http://haskell.org/cabal/ Hackage: Cabal and related projects