[mpich-discuss] MPI I/O SLOW- possible conflicting with communication....code stuck for ever during IO

[hossam]

Hi,

I think i have a well defined problem i wonder if someone can give an
advice.

I am running an MPI code (MPICH2) on a linux cluster.

When i run the code with no IO inside the main runtime loop. It works
perfectly fine on any number of processors and nodes. When i start dumping
data during the loop
the code get stuck for ever after the second or third file.

Everything works perfectly fine on a single processor though.

Now, to make things clearer: When i use ROMIO (MPI IO) it got stuck during
opining the file (MPI_FILE_OPEN).

However, i tried regular open(....) at the root processor and then reducing
the data to the root processor and write there. The code got stuck at the
MPI_REDUCE call.

If i eliminated all the processors communication and just do dump IO (both
ways), it runs fine but it slows down significantly when dumping the data.

I tried on three different clusters(all linux) and i got the same problem.

I don't want say what i think is the problem, i don't really know, but if
the experts here can help i will appreciate.

 Thanks

On Sun, Mar 14, 2010 at 12:50 PM, hossam <hossam.elasrag at gmail.com> wrote:

> Hi,
>
> This is my first post to the mpi-forum. I have a runtime problem related to
> MPI using MPICH2. I wonder if this is the correct forum to post my problem.
> Please let me know so i can proceed forward with my problem details.
>
> Thanks
>
>
>
>
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