GHC compile times (was Re: GHC 6.4.3 is stalled)

Duncan Coutts duncan.coutts at
Tue Jul 25 09:09:53 EDT 2006

On Tue, 2006-07-25 at 13:45 +0100, Joel Reymont wrote:
> On Jul 25, 2006, at 1:34 PM, Christian Maeder wrote:
> > On our solaris sparc machine compiling our main binary (optimized)  
> > takes
> > 3h:38min whereas (only) 55min under linux. At least our sparcs may die
> > out sooner or later.
> Interestingly enough, it takes the 3+ hours to compile GHC 6.5 on my  
> Intel Core-Duo Mac.

BTW, ghc's build system does support parallel make, so if you do have
more than one CPU then you can cut compile times by using
make -j2
(assuming you've got 2 CPUs)

You can also cut compile times by compiling fewer non-core libraries and
by using -fasm rather than -fvia-C.

add these lines to your mk/ (which will not exist unless you
create it):

SRC_HC_OPTS     = -O -fasm
GhcBootLibs     = YES

Note that using GhcBootLibs = YES means you only get a minimal set of
packages, eg no stm, mtl, fgl, QuickCheck etc etc. If that's not to your
liking then you'll need to customise the libraries/Makefile .


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