On Wed, Jul 23, 2008 at 02:24:03PM +0200, Gabriele Fatigati wrote:
> >You could always effect your own parallel IO (e.g., use MPI sends and
> receives to coordinate parallel reads and writes), but >why? It's already
> done in the MPI-IO implementation.
>
> Just a moment: you're saying that i can do fwrite without any lock? OpenMPI
> does this?
You use MPI to describe your I/O regions. In fact, these I/O regions
can even overlap (something that you can't do efficiently with
lock-based approaches). Even better, if you do your I/O
"collectively" the MPI library will optimize the heck out of your
accesses.
When I was learning all this way back when, it took me a long time to
get all the details straight (memory types, file views, tiling,
independent vs. collective), but a few readings of the I/O chapter of
"Using MPI-2" set me straight.
==rob
--
Rob Latham
Mathematics and Computer Science Division A215 0178 EA2D B059 8CDF
Argonne National Lab, IL USA B29D F333 664A 4280 315B
|
![[Flag]](../../../../../community/mirrors/flag-us.gif){kind=small}