On 11/24/05, Robert Ramey <ramey@rrsd.com> 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."