GHC build times on newer MacBook Pros?

austin seipp as at
Tue Aug 23 16:36:05 CEST 2011

I'm using a MBP with a quad core 2gHz Core i7; it has 8 overall
hardware threads. GHC's build process using 'make -j9' or 'make -j12'
totally saturates all my cores. I believe I can clock in a full build
at well under 10 minutes (with BuildFlavor = quick in mk/
For comparison, I also have a dual core 2gHz Core i7 (4 hardware
threads) in a lenovo sitting next to it running Linux, and a full GHC
build takes a bit longer. I can get real numbers later if it's
actually that interesting.

I'd recommend you getting the quad-core machine, if at all possible.

On Tue, Aug 23, 2011 at 4:27 AM, Johan Tibell <johan.tibell at> wrote:
> Hi!
> I'm looking to upgrade my laptop so that I can (among other things)
> compile GHC faster. I'll either get the 13" 2.7GHz dual-core Intel
> Core i7 model or the 15" 2.2GHz quad-core Intel Core i7 model. Anyone
> know if it's worth to get the 15" model? According to these benchmarks
> it should be quite a bit faster:
> but I don't know if I can get enough parallelism out of GHC's build to
> use all 4 cores in the 15" model.
> -- Johan
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