Re: [Caml-list] Re: Is OCaml fast?

[Goswin von Brederlow <goswin-v-b@web.de>]

Gerd Stolpmann <info@gerd-stolpmann.de> writes:

> Am Dienstag, den 23.11.2010, 17:53 +0000 schrieb Isaac Gouy:
>> Christophe TROESTLER <Christophe.Troestler+ocaml <at> umh.ac.be> writes:
>> 
>> > 
>> > On Tue, 23 Nov 2010 02:03:48 +0000, Isaac Gouy wrote:
>> > >
>> > > > C version : 12.11 secs
>> > > > OCaml version : 47.22 secs
>> > > > OCaml version with GC parameters tuned ("interesting alternative" 
>> > >  section) : 12.67 secs
>> > >
>> > > And of course you know because that GC tuned OCaml program is shown 
>> > >  on the
>> > > benchmarks game website 
>> > > http://shootout.alioth.debian.org/u32/program.php?test=binarytrees& 
>> > > lang=ocaml&id=1
>> > 
>> > Since you are here, please explain why C can use memory pools and vec 
>> > tor instructions but tuning the GC of OCaml ― although it is part of  
>> > the standard library ― is considered an “alternative”.
>> 
>> 
>> You seem to be suggesting that "tuning the GC" is considered "alternative" only
>> for OCaml programs.
>> 
>> You seem to be suggesting that "tuning the GC" is considered "alternative" for
>> every task.
>> 
>> Neither is true.
>> 
>> You seem to be suggesting some kind of equivalence between vector instructions
>> and "tuning the GC".
>> You haven't said why they should be considered equivalent.
>> 
>> Nor have you said why you think C should not be allowed to use memory pools.
>
> Quite easy: because you are comparing results that cannot be compared.
> The reader of this benchmark (binary trees) might have the impression
> that C is generally that fast - however, this would be no longer true if
> these binary trees were used as library in a bigger program where using
> memory pools is inappropriate, e.g. because the data managed by the
> binary trees has an unpredictable lifetime.
>
> I do not say that it is complete nonsense to do this comparison, but
> only that it is more specific than a reader would assume. The innocent
> reader expects a comparison of binary tree performance, not of methods
> of managing memory (and this is it finally). The true name of this test
> should be "manage_many_small_memory_cells_where_pools_are_allowed". (It
> would be actually interesting to compare various versions of this test
> with different memory management methods.)
>
> Gerd

So write an ocaml programm that uses and array or bigarray to pool its
memory. That is the same as C does.

MfG
        Goswin