GHC build time graphs

[Karel Gardas]

On 02/13/16 07:57 PM, Karel Gardas wrote:
> On 02/12/16 09:02 PM, Reid Barton wrote:
>>     btw, just recent experience on ARM64 (X-gene board):
>>
>>     bootstrapping 7.10.1 with 7.6.x took: ~120 minutes
>>     bootstrapping 8.0.1 RC2 with 7.10.1 took: ~446 minutes
>>
>>     both run as: ./configure; time make -j8
>>
>>
>> It would be interesting to have the time for bootstrapping 7.10.1 with
>> 7.10.1 too, for comparison.
>
> boostrapping 7.10.1 with 7.10.1 took: ~212 minutes -- but this is not
> comparable directly with numbers above since for whatever reason haddock
> and doc is not build although I've used previous ./configure; time make
> -j8.
>
> Anyway, parallel make itself is not good to use here since the build
> process may also contain some noise of paralellel make fixes and such.
>
> I think more reliable benchmark may be simple build (single-threaded) of
> ghc-cabal here. I'll see what I can do about that.

OK, so not everything is that bad. Benchmarking compilation of GHC 
7.10.1 ghc-cabal tool reveals:

GHC 7.6.3: ~12 minutes
GHC 7.10.1: ~24 minutes
GHC 8.0.1 RC2: ~14 minutes

Please note that GHC 7.6.3 compiles 89 files while GHC 7.10.1 and 8.0.1 
RC2 compile 90 files. Test done on the same x-gene board like the tests 
above for the reference...

Karel