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From: George Bosilca (bosilca_at_[hidden])
Date: 2007-06-20 21:52:51


Jeff,

With the proper MPI_Finalize added at the end of the main function,
your program orks fine with the current version of Open MPI up to 32
processors. Here is the output I got for 4 processors:

I am 2 of 4 WORLD procesors
I am 3 of 4 WORLD procesors
I am 0 of 4 WORLD procesors
I am 1 of 4 WORLD procesors
Initial inttemp 1
Initial inttemp 0
final inttemp 0,0
0, WORLD barrier leaving routine
final inttemp 1,0
1, WORLD barrier leaving routine
Initial inttemp 2
final inttemp 2,0
2, WORLD barrier leaving routine
SERVER Got a DONE flag
Initial inttemp 3
final inttemp 3,0
3, WORLD barrier leaving routine

This output seems to indicate that the program is running to
completion and it does what you expect it to do.

Btw, what version of Open MPI are you using and on what kind of
hardware ?

   george.

On Jun 20, 2007, at 6:31 PM, Jeffrey L. Tilson wrote:

> Hi,
> ANL suggested I post this question to you. This is my second
> posting......but now with the proper attachments.
>
> From: Jeffrey Tilson <jltilson_at_[hidden]>
> Date: June 20, 2007 5:17:50 PM PDT
> To: mpich2-maint_at_[hidden], Jeffrey Tilson <jtilson_at_[hidden]>
> Subject: MPI question/problem
>
>
> Hello All,
> This will probably turn out to be my fault as I haven't used MPI in
> a few years.
>
> I am attempting to use an MPI implementation of a "nxtval" (see the
> MPI book). I am using the client-server scenario. The MPI book
> specifies the three functions required. Two are collective and one
> is not. Only the two collectives are tested in the supplied code.
> All three of the MPI functions are reproduced in the attached code,
> however. I wrote a tiny application to create and free a counter
> object and it fails.
>
> I need to know if this is a bug in the MPI book and a
> misunderstanding on my part.
>
> The complete code is attached. I was using openMPI/intel to compile
> and run.
>
> The error I get is:
>
>> [compute-0-1.local:22637] *** An error occurred in MPI_Comm_rank
>> [compute-0-1.local:22637] *** on communicator MPI_COMM_WORLD
>> [compute-0-1.local:22637] *** MPI_ERR_COMM: invalid communicator
>> [compute-0-1.local:22637] *** MPI_ERRORS_ARE_FATAL (goodbye)
>> mpirun noticed that job rank 0 with PID 22635 on node
>> "compute-0-1.local" exited on signal 15.
>
> I've attempted to google my way to understanding but with little
> success. If someone could point me to
> a sample application that actually uses these functions, I would
> appreciate it.
>
> Sorry if this is the wrong list, it is not an MPICH question and I
> wasn't sure where to turn.
>
> Thanks,
> --jeff
>
> ----------------------------------------------------------------------
> --
>
> /* A beginning piece of code to perform large-scale web
> construction. */
> #include <stdio.h>
> #include <stdlib.h>
> #include <string.h>
> #include "mpi.h"
>
> typedef struct {
> char description[1024];
> double startwtime;
> double endwtime;
> double difftime;
> } Timer;
>
> /* prototypes */
> int MPE_Counter_nxtval(MPI_Comm , int *);
> int MPE_Counter_free( MPI_Comm *, MPI_Comm * );
> void MPE_Counter_create( MPI_Comm , MPI_Comm *, MPI_Comm *);
> /* End prototypes */
>
> /* Globals */
> int rank,numsize;
>
> int main( argc, argv )
> int argc;
> char **argv;
> {
>
> int i,j;
> MPI_Status status;
> MPI_Request r;
> MPI_Comm smaller_comm, counter_comm;
>
>
> int numtimings=0;
> int inttemp;
> int value=-1;
> int server;
>
> //Init parallel environment
>
> MPI_Init( &argc, &argv );
> MPI_Comm_rank( MPI_COMM_WORLD, &rank );
> MPI_Comm_size( MPI_COMM_WORLD, &numsize );
>
> printf("I am %i of %i WORLD procesors\n",rank,numsize);
> server = numsize -1;
>
> MPE_Counter_create( MPI_COMM_WORLD, &smaller_comm, &counter_comm );
> printf("Initial inttemp %i\n",rank);
>
> inttemp = MPE_Counter_free( &smaller_comm, &counter_comm );
> printf("final inttemp %i,%i\n",rank,inttemp);
>
> printf("%i, WORLD barrier leaving routine\n",rank);
> MPI_Barrier( MPI_COMM_WORLD );
> }
>
> //// Add new MPICH based shared counter.
> //// grabbed from http://www-unix.mcs.anl.gov/mpi/usingmpi/examples/
> advanced/nxtval_create_c.htm
>
> /* tag values */
> #define REQUEST 0
> #define GOAWAY 1
> #define VALUE 2
> #define MPE_SUCCESS 0
>
> void MPE_Counter_create( MPI_Comm oldcomm, MPI_Comm * smaller_comm,
> MPI_Comm * counter_comm )
> {
> int counter = 0;
> int message, done = 0, myid, numprocs, server, color,ranks[1];
> MPI_Status status;
> MPI_Group oldgroup, smaller_group;
>
> MPI_Comm_size(oldcomm, &numprocs);
> MPI_Comm_rank(oldcomm, &myid);
> server = numprocs-1; /* last proc is server */
> MPI_Comm_dup( oldcomm, counter_comm ); /* make one new comm */
> if (myid == server) color = MPI_UNDEFINED;
> else color =0;
> MPI_Comm_split( oldcomm, color, myid, smaller_comm);
>
> if (myid == server) { /* I am the server */
> while (!done) {
> MPI_Recv(&message, 1, MPI_INT, MPI_ANY_SOURCE,
> MPI_ANY_TAG,
> *counter_comm, &status );
> if (status.MPI_TAG == REQUEST) {
> MPI_Send(&counter, 1, MPI_INT, status.MPI_SOURCE,
> VALUE,
> *counter_comm );
> counter++;
> }
> else if (status.MPI_TAG == GOAWAY) {
> printf("SERVER Got a DONE flag\n");
> done = 1;
> }
> else {
> fprintf(stderr, "bad tag sent to MPE counter\n");
> MPI_Abort(*counter_comm, 1);
> }
> }
> MPE_Counter_free( smaller_comm, counter_comm );
> }
> }
>
> /*******************************/
> int MPE_Counter_free( MPI_Comm *smaller_comm, MPI_Comm *
> counter_comm )
> {
> int myid, numprocs;
>
> MPI_Comm_rank( *counter_comm, &myid );
> MPI_Comm_size( *counter_comm, &numprocs );
>
> if (myid == 0)
> MPI_Send(NULL, 0, MPI_INT, numprocs-1, GOAWAY, *counter_comm);
>
> MPI_Comm_free( counter_comm );
>
> if (*smaller_comm != MPI_COMM_NULL) {
> MPI_Comm_free( smaller_comm );
> }
> return 0;
> }
>
> /************************/
> int MPE_Counter_nxtval(MPI_Comm counter_comm, int * value)
> {
> int server,numprocs;
> MPI_Status status;
>
> MPI_Comm_size( counter_comm, &numprocs );
> server = numprocs-1;
> MPI_Send(NULL, 0, MPI_INT, server, REQUEST, counter_comm );
> MPI_Recv(value, 1, MPI_INT, server, VALUE, counter_comm,
> &status );
> return 0;
> }
>
>
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