Re: [Caml-list] Accelerating compilation

[Francois Berenger <berenger@riken.jp>]

On 09/11/2013 10:46 PM, Wojciech Meyer wrote:
> What are you trying to prove here?

I am not trying to prove anything.
I just manage to show something, which is the whole point of a good plot.

 > Makefiles will be always faster as
> mentioned before, however there is still space for vast improvement, the
> biggest elephant here being slow scanning. Patches welcome.
>
> Also, it does not show the convenience of using ocamlbuild, in
> particular dynamic dependency resolver, nice language for specyfing
> complex rules, tags, and VPATH build that just works (does your makefile
> VPATH at all?)
>
>
>
> On Wed, Sep 11, 2013 at 2:00 PM, Francois Berenger <berenger@riken.jp
> <mailto:berenger@riken.jp>> wrote:
>
>     On 9/7/13 5:51 AM, Fabrice Le Fessant wrote:
>
>         On Fri, Sep 6, 2013 at 5:20 PM, Romain Bardou
>         <romain.bardou@inria.fr <mailto:romain.bardou@inria.fr>> wrote:
>
>                     3) Parallel compilation in Ocamlbuild
>
>                     Of course it would help but it is not easy to
>                     implement so I'm just
>                     putting it there to be exhaustive.
>
>
>                 I'm not sure what you are referring to, OCamlBuild does
>                 already
>                 support parallel builds.
>
>
>             Does it? I actually thought the -j option was ignored.
>
>             I just did a quick test and I gain about 5 seconds with -j
>             on a 1min15
>             build (I had cleaned, recompiled and recleaned before so
>             that caching by
>             the file system would not impact the result too much), so it
>             does seem
>             to be a *little* faster :)
>
>
>         FWIW, I recently compiled Merlin with both ocamlbuild and ocp-build,
>         on a quad-core with "-j 10" for both (the link to the ocp-build
>         description file is in the latest OCamlPro's report), ocamlbuild
>         needs
>         13s where ocp-build only needs 4s to compile everything.
>
>
>     This morning, I played with a Makefile and ocamlbuild
>     to build batteries-included from a clean source tree.
>
>     The Makefile was provided by Cedric Cellier.
>
>     Here follows the wallclock times to build on my eight cores machine.
>
>     #You can plot them like this:
>     cat <<EOF > make_Vs_ocamlbuild.data
>     #nprocs Makefile ocamlbuild
>     1 14.52 21.43
>     2 6.84 17.57
>     3 4.95 16.44
>     4 4.18 15.95
>     5 3.70 15.67
>     6 3.36 15.62
>     7 3.12 15.54
>     8 3.03 15.292
>     EOF
>     gnuplot -persist <<EOF
>     set title 'make Vs ocamlbuild'
>     set xlabel 'nprocs'
>     set ylabel 'wallclock time(s)'
>     plot 'make_Vs_ocamlbuild.data' u 1:2 w lines title 'time -p make
>     fast -j np', \
>                                  '' u 1:3 w lines title 'ocamlbuild -j np'
>     EOF
>
>
>
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