MPI_Barrier无法正常运行

我写了下面的C应用程序来帮助我理解MPI，以及为什么MPI_Barrier()在我的大型c++应用程序中不起作用。但是，我能够在我的大型应用程序中用一个小得多的C应用程序再现我的问题。实际上，我在for循环中调用MPI_Barrier()，并且MPI_Barrier()对所有节点都是可见的，但是在循环的2次迭代之后，程序变成了死锁。任何想法吗?

#include <mpi.h>
#include <stdio.h>
int main(int argc, char* argv[]) {
    MPI_Init(&argc, &argv);
    int i=0, numprocs, rank, namelen;
    char processor_name[MPI_MAX_PROCESSOR_NAME];
    MPI_Comm_size(MPI_COMM_WORLD, &numprocs);
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Get_processor_name(processor_name, &namelen);
    printf("%s: Rank %d of %dn", processor_name, rank, numprocs);
    for(i=1; i <= 100; i++) {
            if (rank==0) printf("Before barrier (%d:%s)n",i,processor_name);
            MPI_Barrier(MPI_COMM_WORLD);
            if (rank==0) printf("After barrier (%d:%s)n",i,processor_name);
    }
    MPI_Finalize();
    return 0;
}

alienone: Rank 1 of 4
alienfive: Rank 3 of 4
alienfour: Rank 2 of 4
alientwo: Rank 0 of 4
Before barrier (1:alientwo)
After barrier (1:alientwo)
Before barrier (2:alientwo)
After barrier (2:alientwo)
Before barrier (3:alientwo)

我正在使用GCC 4.4，从Ubuntu 10.10存储库打开MPI 1.3。

另外，在我的c++应用程序中，MPI广播不起作用。只有一半的节点接收到广播，其他的都在等待。

提前感谢您的任何帮助或见解!

更新:升级到Open MPI 1.4.4，从源代码编译到/usr/local/。

Update:将GDB附加到正在运行的进程中显示了一个有趣的结果。在我看来，MPI系统在屏障处死亡，但MPI仍然认为程序正在运行:

附加GDB产生一个有趣的结果。似乎所有节点都在MPI障碍处死亡，但MPI仍然认为它们正在运行:

0x00007fc235cbd1c8 in __poll (fds=0x15ee360, nfds=8, timeout=<value optimized out>) at   ../sysdeps/unix/sysv/linux/poll.c:83
83  ../sysdeps/unix/sysv/linux/poll.c: No such file or directory.
    in ../sysdeps/unix/sysv/linux/poll.c
(gdb) bt
#0  0x00007fc235cbd1c8 in __poll (fds=0x15ee360, nfds=8, timeout=<value optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:83
#1  0x00007fc236a45141 in poll_dispatch () from /usr/local/lib/libopen-pal.so.0
#2  0x00007fc236a43f89 in opal_event_base_loop () from /usr/local/lib/libopen-pal.so.0
#3  0x00007fc236a38119 in opal_progress () from /usr/local/lib/libopen-pal.so.0
#4  0x00007fc236eff525 in ompi_request_default_wait_all () from /usr/local/lib/libmpi.so.0
#5  0x00007fc23141ad76 in ompi_coll_tuned_sendrecv_actual () from /usr/local/lib/openmpi/mca_coll_tuned.so
#6  0x00007fc2314247ce in ompi_coll_tuned_barrier_intra_recursivedoubling () from /usr/local/lib/openmpi/mca_coll_tuned.so
#7  0x00007fc236f15f12 in PMPI_Barrier () from /usr/local/lib/libmpi.so.0
#8  0x0000000000400b32 in main (argc=1, argv=0x7fff5883da58) at barrier_test.c:14
(gdb) 

:我也有这个代码:

#include <mpi.h>
#include <stdio.h>
#include <math.h>
int main( int argc, char *argv[] )  {
int n = 400, myid, numprocs, i;
double PI25DT = 3.141592653589793238462643;
double mypi, pi, h, sum, x;
MPI_Init(&argc,&argv);
MPI_Comm_size(MPI_COMM_WORLD,&numprocs);
MPI_Comm_rank(MPI_COMM_WORLD,&myid);
printf("MPI Rank %i of %i.n", myid, numprocs);
while (1) {
    h   = 1.0 / (double) n;
    sum = 0.0;
    for (i = myid + 1; i <= n; i += numprocs) {
        x = h * ((double)i - 0.5);
        sum += (4.0 / (1.0 + x*x));
    }
    mypi = h * sum;
    MPI_Reduce(&mypi, &pi, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);
    if (myid == 0)
        printf("pi is approximately %.16f, Error is %.16fn",  pi, fabs(pi - PI25DT));
}
MPI_Finalize();
return 0;
}

尽管存在无限循环，但循环中的printf()只有一个输出:

mpirun -n 24 --machinefile /etc/machines a.out 
MPI Rank 0 of 24.
MPI Rank 3 of 24.
MPI Rank 1 of 24.
MPI Rank 4 of 24.
MPI Rank 17 of 24.
MPI Rank 15 of 24.
MPI Rank 5 of 24.
MPI Rank 7 of 24.
MPI Rank 16 of 24.
MPI Rank 2 of 24.
MPI Rank 11 of 24.
MPI Rank 9 of 24.
MPI Rank 8 of 24.
MPI Rank 20 of 24.
MPI Rank 23 of 24.
MPI Rank 19 of 24.
MPI Rank 12 of 24.
MPI Rank 13 of 24.
MPI Rank 21 of 24.
MPI Rank 6 of 24.
MPI Rank 10 of 24.
MPI Rank 18 of 24.
MPI Rank 22 of 24.
MPI Rank 14 of 24.
pi is approximately 3.1415931744231269, Error is 0.0000005208333338

任何想法吗?