Re: [boost] [serialization] fast array serialization (10x speedup)

From: Felipe Magno de Almeida (felipe.m.almeida_at_[hidden])
Date: 2005-11-24 14:20:41

On 11/24/05, Robert Ramey <ramey_at_[hidden]> wrote:

[snip]

> The current binary archives are implemented in terms of
> stream i/o.  This was convenient to do so and has worked
> well.  But basing the implemention on streams results
> in a slow implemenation.  The documentation explicitly
> states that archives do not have to be implemented in terms
> of streams. The binary archives don't use any of the
> stream interface other than read(.. write(.. so it would
> be quite easy to make another binary archive which isn't
> based on stream i/o.  It could be based on fread/fwrite.
> Given that the concern of the proposal of the authors
> is to make the library faster for machine to machine
> communication and the desired protocols (MPI) don't
> use file i/o, the fastest would be just a buffer
> say buffer_archve which doesn't do any i/o at all.
> It would just fill up a user specified buffer whose
> address was handed at buffer_archive construction time.
> This would totally eliminate stream i/o from the equation.
>
> Note that this would be easy to do. Just clone binary_archive,
> and modify it so it doesn't use a stream.  (probably don't want
> to derive from basic_binary_archive). I would guess that
> that would take about a couple of hours at most.
>
> I would be surprised to see if the 10x speed up still exists
> with this "buffered_archive".

Creating a "buffered_archive" wouldnt require copying? And as Matthias
have already put, it is an unacceptable overhead. I'm having some
ideas about a 'fake_buffered'_archive.

best regards,
--
   Felipe Magno de Almeida
Developer from synergy and Computer Science student from State
University of Campinas(UNICAMP).
Unicamp: http://www.ic.unicamp.br
Synergy: http://www.synergy.com.br
"There is no dark side of the moon really. Matter of fact it's all dark."