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Subject: Re: [OMPI users] nonblocking MPI_File_iwrite() does block?
From: Barrett, Brian W (bwbarre_at_[hidden])
Date: 2009-11-23 15:32:24

On 11/23/09 8:42 AM, "Rob Latham" <robl_at_[hidden]> wrote:

> Is it OK to mention MPICH2 on this list? I did prototype some MPI
> extensions that allowed ROMIO to do true async I/O (at least as far
> as the underlying operating system supports it). If you really need
> to experiment with async I/O, I'd love to hear your experiences.

Rob -

Funny you should mention that code. I was looking into a compile error in
OMPI on a strange platform last week (while travelling to SC, of course) and
was realizing that I had no idea what I was doing when I integrated ROMIO
into Open MPI many years ago, did it horribly, and want to clean it up.

Anyway, you're talking about all the MPIX_Grequest interface used in ROMIO,
right? Do you have documentation of that API anywhere (even a header file
with some comments)? I'm going to try to clean up how we integrate into
ROMIO during the holiday break, and it might make sense to implement the
extended API so that we can give some async I/O behavior as well. From
looking at the ROMIO usage, I think OMPI has all the internal pieces to put
together the API pretty quickly, so it might be an option. Any thoughts you
have on the subject would be greatly appreciated.