On Tue, Oct 7, 2014 at 11:26 AM, <p.k.f.holzensp...@utwente.nl> wrote: > Wait, wait, wait! I wasn't talking about a parallel *runtime*. Nothing > changes there. All I'm talking about is something that is a very old issue > that never got added / solved / resolved. Somewhere on the commentary, or the > mailing list, I seem to recall that the generation of Uniques was the > bottleneck for the parallelisation of GHC *Itself*. It's about having a > compiler using multiple threads and says nothing about programs coming out of > it.
OK, cool. Just making sure. :) > I'm all with you on embedded processors and that kind of stuff, but I don't > see a pressing need to compile *on* them. Isn't all ARM-stuff assuming > cross-compilation? No, not all ARM builds assume cross compilation. In fact, if you want a fully working GHC, cross compilation is impossible: you cannot cross compile GHCi, meaning you can't use Template Haskell (as well as some of the linker features, I believe). However, I don't think this change impacts building GHC at all, since we get parallelism through 'make', not through GHC itself (and on low-end systems, parallelism in the build system is crucial and really necessary.) So I assume your change would mean 'ghc -j' would not work for 32bit. I still consider this a big limitation, one which is only due to an implementation detail. But we need to confirm this will actually fix any bottlenecks first though before getting to that point. > Ph. > > > ________________________________________ > From: mad....@gmail.com <mad....@gmail.com> on behalf of Austin Seipp > <aus...@well-typed.com> > Sent: 07 October 2014 17:46 > To: Holzenspies, P.K.F. (EWI) > Cc: ghc-devs@haskell.org > Subject: Re: Again: Uniques in GHC > > On Tue, Oct 7, 2014 at 1:32 AM, <p.k.f.holzensp...@utwente.nl> wrote: >> Yes, this approach to a parallel GHC would only work on 64-bit machines. The >> idea is, I guess, that we're not going to see a massive demand for parallel >> GHC running on multi-core 32-bit systems. In other words; 32-bit systems >> wouldn't get a parallel GHC. > > Let me make sure I'm understanding this correctly: in this particular > proposed solution, the side effect would be that we no longer have a > capable 32bit runtime which supports multicore parallelism? > > Sorry, but I'm afraid this approach is pretty much unacceptable IMO, > for precisely the reason outlined in your last sentence. 32bit systems > are surprisingly commen. I have several multicore 32bit ARMv7 machines > on my desk right now, for example. And there are a lot more of those > floating around than you might think. > > If that's the 'cure', I think I (and other users) would consider it > far worse than the disease. > >> Regards, >> Philip >> >> >> _______________________________________________ >> ghc-devs mailing list >> ghc-devs@haskell.org >> http://www.haskell.org/mailman/listinfo/ghc-devs >> > > -- > Regards, > > Austin Seipp, Haskell Consultant > Well-Typed LLP, http://www.well-typed.com/ > -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/ _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs
