On 17 February 2016 at 14:31, Tuncer Ayaz <tuncer.a...@gmail.com> wrote:
> On 17 February 2016 at 07:40, Evan Laforge <qdun...@gmail.com> wrote: > > > My impression from the reddit thread is that three things are going > > on: > > > > 1 - cabal has quite a bit of startup overhead > > 2 - ghc takes a long time on certain inputs, e.g. long list literals. > > There are probably already tickets for these. > > In my experience GHC startup overhead (time) has increased quite a > lot somewhere in 7.x. I don't know if it's the cause, but perhaps > dyn libs may be part of the reason. I'm not sure because I once (7.8 > I believe) tried to build without dynlink support and couldn't > measure a substantial improvement. > > So, if you start ghc(i) for the first time from a spinning disk, > it's very noticeable and quite a delay. Once it's cached, it's fast, > so I think it's primarily due to reading stuff from disk. > > Just to mention the ideal overhead: anything below 400ms is small > enough to not disrupt the flow and feels responsive. Go over 1s and > it breaks. Freshly booted machine with an SSD required 2 seconds for GHCi, so maybe it's just that there's a lot more stuff to load, which leads me to the next question: (better) dead code elimination would probably help, where it at minimum only includes modules used, with a future improvement of skipping unused functions, etc. as well, but I don't know enough about GHC's DCE to talk about it. _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
