Re: [Caml-list] Memory allocation nano-benchmark.

[Christian Szegedy <szegedy@t-online.de>]

Marwan Burelle wrote:

>On Thu, 10 Feb 2005 09:59:53 -0500, John Prevost <j.prevost@gmail.com> wrote:
>  
>
>>In a program that allocates one very large chunk of memory, I suspect
>>you will find that both C and O'Caml do a lot better when... you
>>allocated as one very large chunk of memory (or, if need be, a *tiny*
>>number of large chunks) instead of as many small chunks of memory.
>>    
>>
>
>It also depends on malloc, on Linux it sometimes works
>"optimisticaly", that is, it won't realy allocate memory unless you
>use it (leading to some strange out of memory error, since it can
>return a non-Null pointer even if memory isn't available.) So, a C
>program with a lot of malloc and no usage of the memory allocated
>could be faster than it realy is ...
>
>My 2cc.
>
Actually, I have *filled* the arrays, as it may be clear from
the code. This example was extracted from a program which
massively shuffles around the content of this 3-dimensional grid.
(Both work fine and yield identical output.)

To my astonishment, the OCaml was a bit faster than C when
working on the grid, but the speed of allocation was nowhere
near to that of the C version.

This was a surprise to me, since I thought that OCaml is quite
competitive in this regard.