Dear all,

I am all set with your suggestions and my program is working quite well without any "unexpected message" since then, thanks again.

However now I am facing a small problem I describe next.

My receiver process receives actually 2 types of messages (2 different tags):

the basic tag means that the message is a "data message" ("data" tag) that should be processed.
the second one means that the worker process is done and it will send no more messages ("end_of_processing" tag).

Once all worker processes send their end_of_processing tag, the receiver process finishes its execution.

The problem I noticed is that some of the last messages sent by the worker processes were not being processed. I think the problem is related with the logic I am using with MPI_WAITANY in the receiver process. I am simply counting the number of end_of_processing messages received and if it reaches the number of worker processes, I finish the execution without checking if there are more messages to be received at the MPI_WAITANY queue.

As the order that messages arrive is not relevant for MPI_WAITANY I think that my logic forgets some of the messages at the end of the queue. Is this right?

Is there any way to check if there is any pending request to be processed?

Best regards,

Luiz

On 16 January 2014 16:57, "Antonio J. Peña" <apenya@mcs.anl.gov> wrote:

A profiling of both of your codes would help to understand where the time is spent and the difference between them in terms of performance.

Antonio

On 01/16/2014 12:47 PM, Luiz Carlos da Costa Junior wrote:
Yes, I am comparing original x new implementation.

The original implementation is as follows.

c-----------------------------------------------------------------------

subroutine my_receiver_original

c ------------------------------------------------------------------

(...)

c Local

c -----

integer*4 m_stat(MPI_STATUS_SIZE)

character card*(zbuf) ! buffer for messages received

do while( keep_receiving )

call MPI_RECV(card, zbuf, MPI_CHARACTER,

. MPI_ANY_SOURCE, M_RECCSV, MY_COMM,

. m_stat, m_ierr )

c Process message: disk IO

c ---------------

<DO SOMETHING>

if( SOMETHING_ELSE ) then

keep_receiving = .false.

end if

end do

(...)

return

end

Regards,

Luiz

On 16 January 2014 16:19, Balaji, Pavan <balaji@mcs.anl.gov> wrote:

On Jan 16, 2014, at 12:16 PM, Luiz Carlos da Costa Junior <lcjunior@ufrj.br> wrote:
> No, these failures don't occur all the time. I have a successful run (with my original implementation) which I am using as the base case for comparison.

What are the two cases you are comparing? Original implementation vs. new implementation? What’s the original implementation?

— Pavan

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-- Antonio J. Peña Postdoctoral Appointee Mathematics and Computer Science Division Argonne National Laboratory 9700 South Cass Avenue, Bldg. 240, Of. 3148 Argonne, IL 60439-4847 apenya@mcs.anl.gov www.mcs.anl.gov/~apenya
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