Given the vectorisation code is in its own subdirectory already, it’s quite easy to spot in a grep, I would say.
Manuel > Richard Eisenberg <e...@cis.upenn.edu>: > > With all due respect to Manuel's request, could I opt for a different > resolution? I frequently (several times during most minutes of GHC > programming) grep the GHC source code for this or that. If the vectorisation > code is CPP'd away but still present in the compiler/ directory, these greps > will find hits in the code. Furthermore, without the specific knowledge that > there is a `#if 0` at the top of the file, the code will look quite active. > Of course, I could modify my grep macro to skip the vectorise directory, but > the next dev down the road might not know to do this. > > Here's an alternate suggestion: in SimplCore, keep the call to vectorise > around, but commented out (not just with CPP, for better syntax > highlighting). Include a Note explaining what `vectorise` does and why it's > not there at the moment. However, move the actual vectorisation code > somewhere else in the repo, outside of the source directories (`utils`? a new > `attic` directory?). > > Manuel, is this acceptable to you? Other devs, thoughts? Perhaps we should > also make a Trac ticket asking for some love to be given to this feature. > > Thanks, > Richard > > On Jan 19, 2015, at 9:21 AM, Simon Peyton Jones <simo...@microsoft.com> wrote: > >> Austin, (or anyone else) >> >> Manuel says: >> >> | > Would it be ok if we left it in the repo, but CPP'd it out so that >> | we >> | > didn't compile everything? (The DPH library is in the same state at >> | > the moment.) >> | > >> | > It might suffer bit-rot, but it’d still be there for resurrection. >> | >> | Sure, that’s ok. >> >> Could you action this? Just avoid compiling anything in 'vectorise/', using >> (I suppose) cpp to create a stub where necessary. >> >> Leave enough comments to explain! >> >> Simon >> >> | >> | I hope everything is fine in Cambridge! >> | Manuel >> | >> | > | -----Original Message----- >> | > | From: ghc-devs [mailto:ghc-devs-boun...@haskell.org] On Behalf Of >> | > | Manuel M T Chakravarty >> | > | Sent: 16 January 2015 02:58 >> | > | To: Richard Eisenberg >> | > | Cc: ghc-devs@haskell.org Devs >> | > | Subject: Re: vectorisation code? >> | > | >> | > | [Sorry, sent from the wrong account at first.] >> | > | >> | > | We currently don’t have the resources to work on DPH. I would >> | > | obviously prefer to leave the code in, in the hope that we will be >> | > | able to return to it. >> | > | >> | > | Manuel >> | > | >> | > | > Richard Eisenberg <e...@cis.upenn.edu>: >> | > | > >> | > | > Hi devs, >> | > | > >> | > | > There's a sizable number of modules in the `vectorise` >> | > | subdirectory of GHC. I'm sure these do all sorts of wonderful >> | > | things. But what, exactly? And, does anyone make use of these >> | wonderful things? >> | > | > >> | > | > A quick poking through the code shows a tiny link between the >> | > | vectorise code and the rest of GHC -- the function `vectorise` >> | > | exported from the module `Vectorise`, which is named in exactly >> | one >> | > | place from SimplCore. From what I can tell, the function will be >> | > | called only when `-fvectorise` is specified, and then it seems to >> | > | interact with a {-# VECTORISE #-} pragma. However, `{-# VECTORISE >> | > | #-}` doesn't appear in the manual at all, and `-fvectorise` is >> | > | given only a cursory explanation. It seems these work with DPH... >> | > | which has been disabled, no? Searching online finds several hits, >> | > | but nothing more recent than 2012. >> | > | > >> | > | > I hope this question doesn't offend -- it seems that >> | > | vectorisation probably has amazing performance gains. Yet, the >> | > | feature also seems unloved. In the meantime, compiling (and >> | > | recompiling, and >> | > | recompiling...) the modules takes time, as does going through >> | them >> | > | to propagate changes from elsewhere. If this feature is truly >> | > | orphaned, unloved, and unused at the moment, is it reasonable to >> | > | consider putting it on furlough? >> | > | > >> | > | > Thanks, >> | > | > Richard >> | > | > _______________________________________________ >> | > | > ghc-devs mailing list >> | > | > ghc-devs@haskell.org >> | > | > http://www.haskell.org/mailman/listinfo/ghc-devs >> | > | >> | > | _______________________________________________ >> | > | ghc-devs mailing list >> | > | ghc-devs@haskell.org >> | > | http://www.haskell.org/mailman/listinfo/ghc-devs >> >> _______________________________________________ >> ghc-devs mailing list >> ghc-devs@haskell.org >> http://www.haskell.org/mailman/listinfo/ghc-devs >> > > _______________________________________________ > ghc-devs mailing list > ghc-devs@haskell.org > http://www.haskell.org/mailman/listinfo/ghc-devs _______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://www.haskell.org/mailman/listinfo/ghc-devs
