Re: [Caml-list] Very slow compilation

[Raphael Proust <raphlalou@gmail.com>]

When working with ocamlduce (a few years ago) the same problem was
raised. A simple thing that can greatly reduce typing time is putting
explicit type annotations. Although the verbosity is increased it is
not that much of a burden if the annotated parts do not evolve too
much.

The same probably applies with plain ocaml. (It might be that
objects/classes typing is more complicated due to sub-typing, although
someone with insider knowledge would know better.)

On Sun, Mar 11, 2012 at 9:39 AM, Gabriel Scherer
<gabriel.scherer@gmail.com> wrote:
> I can't comment on the type-checker internals, but a general first
> step would be to make sure that you don't recompile things that you
> don't need to.
>
> If you change the *implementation* of a module without changing its
> interface, you should not have to recompile any other module, at least
> when using bytecode compilation. You need not recompile even the
> modules that depend on this -- there is only an
> interface-dependency. With native compilation, the compiler can
> inspect depending modules to perform some cross-module optimizations,
> so there will be an implementation-dependency by default, but you can
> disable it -- the .cmx for bar.ml won't depend on its dependency
> foo.ml if foo.cmx is not available at compile time. It's simpler to
> just use ocamlc for development. It's also faster at code generation,
> but apparently your bottleneck is typing.
>
> To fully benefit from separate compilation, you may want to have
> a slightly more fine-grained separation of you program into
> compilation units. If a given module interface can be split in two
> parts, one that evolves slowly and on which a lot of modules depend,
> and one that is little used outside but changes frequently, it's a big
> win to split it into two separate module interfaces -- when you can,
> eg. the whole thing is not encapsulated as a functor.
>
> On Sun, Mar 11, 2012 at 9:11 AM, SerP <serp256@gmail.com> wrote:
>> We encountered a problem of a slow compilation. When the project grew up,
>> the time of compilation increased considerably. We have many classes and
>> objects, and the type checking of objects and classes performs very slowly.
>> I have Core i3 3GHz iMac, and the average compilation time of one module is
>> 7-13 seconds. The entire projet is compiled within 10-15 minutes. The major
>> part of the time is taken by "Typemod.type_implementation", which include
>> many calls of Ctype.unify (80% of compilation time). Now, it is getting hard
>> and slow to develop the projetct, are there any ways to accelarate it? It is
>> difficult to get all fine points, but I wish I could make the process
>> faster. Thanks for any help or comments. Looking forward to your reply
>
>
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-- 
_______
Raphael