Re: [Caml-list] Is OCaml fast?

[bluestorm <bluestorm.dylc@gmail.com>]

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On Mon, Nov 22, 2010 at 3:04 PM, Gerd Stolpmann <info@gerd-stolpmann.de>wrote:

> I think the shootout is not a good data source. There are definitely
> some very poor Ocaml results there, so I'd guess the shootout got
> recently more attention by enthusiasts of other languages, and the
> current Ocaml programs there are not very good. (I remember Ocaml was #1
> at the shootout a few years ago, faster than C.) So maybe a good
> opportunity to post better Ocaml solutions there?
>

As Sylvain noticed, some (in not most) of the OCaml poor performances in the
shootout are actually not due to bad OCaml programs, but to arbitrary
restrictions in the shootout rules. For example, one of the bad-performing
benchmark for OCaml is the binary-tree benchmark, where it is nearly four
times slower than C, but on closer inspection you discover that this is due
to the arbitrary choice to forbid any change of the GC parameters. With
appropriate GC parameters, the very same OCaml program is exactly as fast as
C.

http://shootout.alioth.debian.org/u32/performance.php?test=binarytrees

« Note: these programs are being measured with *the default initial heap
size* - the measurements may be very different with a larger initial heap
size or GC tuning. »
C version : 12.11 secs
OCaml version : 47.22 secs
OCaml version with GC parameters tuned ("interesting alternative" section) :
12.67 secs


Therefore, there is nothing that can be changed to the OCaml submission for
this benchmark to improve performances, except changing the default GC
parameters; while this might be a good idea in general, changing it only for
the sake of shootout-obsessed people is ridiculous.

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