Parallel --make (GHC build times on newer MacBook Pros?)
brandon_m_moore at yahoo.com
Sat Aug 27 05:25:00 CEST 2011
> From: Evan Laforge <qdunkan at gmail.com>
> Sent: Friday, August 26, 2011 6:35 PM
> Subject: Re: GHC build times on newer MacBook Pros?
> On Tue, Aug 23, 2011 at 10:24 AM, David Terei <davidterei at gmail.com>
>> I have a 16 core machine at work (with 48GB of ram, a perk of the job
>> :)). GHC can saturate them all. Can validate GHC in well under 10
>> minutes on it.
> To wander a bit from the topic, when I first saw this I thought "wow,
> ghc builds in parallel now, I want that" but then I realized it's
> because ghc itself uses make, not --make. --make's automatic
> dependencies are convenient, but figuring out dependencies on every
> build and not being parallel means make should be a lot faster. Also,
> --make doesn't understand the hsc->hs link, so in practice I have to
> do a fair amount of manual dependencies anyway. So it inspired me to
> try to switch from --make to make for my own project.
I'm confused by this as well. Parallelizing --make was one of the
first case studies in the smp runtime paper, section 7 in
Haskell on a Shared-Memory Multiprocessor
There's also a trac ticket
http://hackage.haskell.org/trac/ghc/ticket/910with a vague comment that the patch from the paper
"almost certainly isn't ready for prime time",
but I haven't
seen any description of specific problems.
More information about the Glasgow-haskell-users