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Reply-To: <jon@ffconsultancy.com>
From: "Jon Harrop" <jon@ffconsultancy.com>
To: "'Alain Frisch'" <alain@frisch.fr>
Cc: <caml-list@inria.fr>
References: <00ba01ce200c$d23f1910$76bd4b30$@ffconsultancy.com> <5140BD88.7090905@frisch.fr>
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Date: Wed, 13 Mar 2013 19:44:08 -0000
Organization: Flying Frog Consultancy Ltd.
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Subject: RE: [Caml-list] Case study in optimization: porting a compiler from
 OCaml to F#

Alain Frisch wrote:
> Too bad, because the really interesting part would to know (i) what kind
of
> optimizations you had to do on the F# version (and in particular whether
> they make us of parallelism),

* Replaced the use of exceptions for control flow with variant types.
* Replaced use of fprintf with lower-level .NET functions.
* Parallelized some of the symbolic code.
* Algorithmic optimization to a search function.

> (ii) whether (some of) those optimizations could be applicable to the
OCaml
> version as well, and

* No need to replace exceptions in OCaml.
* No need to replace printf and friends in OCaml.
* Could try to parallelize the OCaml but it would be hard to do efficiently.
* Algorithmic optimization could also be done to the OCaml (IIRC, this was a
fairly minor speedup).

> (iii) how much effort you initially put into optimizing the OCaml version
(just
> tweaking the GC parameters can easily give very substantial speedups for
> symbolic processing).

None. I didn't change the OCaml code at all and didn't try different GC
parameters. However, it had already been quite heavily optimized.

Cheers,
Jon.