Thanks for the replies and sorry for the incomplete information. I should have written that I get a segfault for np=2 but not np=1. Find the exact error message below. I've also tried the program Jeff sent and I get the same segfault as before for all np>1. I'll try to checkout and build the development version and see if I can reproduce. =================================================================================== = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES = PID 7703 RUNNING AT 30-9-81.wireless.csail.mit.edu = EXIT CODE: 11 = CLEANING UP REMAINING PROCESSES = YOU CAN IGNORE THE BELOW CLEANUP MESSAGES =================================================================================== YOUR APPLICATION TERMINATED WITH THE EXIT STRING: Segmentation fault: 11 (signal 11) This typically refers to a problem with your application. Please see the FAQ page for debugging suggestions On Tue, Jul 26, 2016 at 12:16 PM, Jeff Hammond <[email protected]> wrote:

Indeed, Rob is right. I only tested np<=2. Didn't see failure until nproc=16 because of how malloc works but in any case, it is trivial to fix this by allocating C to be nproc elements.

Jeff

#include <mpi.h>

#include <stdio.h>

#include <stdlib.h>

int main(int argc, char *argv[])

{

MPI_Init(&argc, &argv);

MPI_Comm comm = MPI_COMM_WORLD;

uint64_t *A, *C;

int rnk, siz;

MPI_Comm_rank(comm, &rnk);

MPI_Comm_size(comm, &siz);

A = calloc(1, sizeof(uint64_t));

C = calloc(siz, sizeof(uint64_t));

A[0] = rnk + 1;

MPI_Allgather(A, 1, MPI_UINT64_T, C, 1, MPI_UINT64_T, comm);

free(C);

free(A);

MPI_Finalize();

return 0;

}

On Tue, Jul 26, 2016 at 9:00 AM, Rob Latham <[email protected]> wrote:

...

On 07/26/2016 10:17 AM, Andreas Noack wrote:

...

On my El Capitan macbook I get a segfault when running the program below with more than a single process but only when MPICH has been compiled with Clang.

I don't get that good debug info but here is some of what I got

valgrind is pretty good at sussing out these sorts of things:

==18132== Unaddressable byte(s) found during client check request ==18132== at 0x504D1D7: MPIR_Localcopy (helper_fns.c:84) ==18132== by 0x4EC8EA1: MPIR_Allgather_intra (allgather.c:169) ==18132== by 0x4ECA5EC: MPIR_Allgather (allgather.c:791) ==18132== by 0x4ECA7A4: MPIR_Allgather_impl (allgather.c:832) ==18132== by 0x4EC8B5C: MPID_Allgather (mpid_coll.h:61) ==18132== by 0x4ECB9F7: PMPI_Allgather (allgather.c:978) ==18132== by 0x4008F5: main (noack_segv.c:18) ==18132== Address 0x6f2f138 is 8 bytes after a block of size 16 alloc'd ==18132== at 0x4C2FB55: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==18132== by 0x4008B0: main (noack_segv.c:15) ==18132== ==18132== Invalid write of size 8 ==18132== at 0x4C326CB: memcpy@@GLIBC_2.14 (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==18132== by 0x504D31B: MPIR_Localcopy (helper_fns.c:84) ==18132== by 0x4EC8EA1: MPIR_Allgather_intra (allgather.c:169) ==18132== by 0x4ECA5EC: MPIR_Allgather (allgather.c:791) ==18132== by 0x4ECA7A4: MPIR_Allgather_impl (allgather.c:832) ==18132== by 0x4EC8B5C: MPID_Allgather (mpid_coll.h:61) ==18132== by 0x4ECB9F7: PMPI_Allgather (allgather.c:978) ==18132== by 0x4008F5: main (noack_segv.c:18) ==18132== Address 0x6f2f138 is 8 bytes after a block of size 16 alloc'd ==18132== at 0x4C2FB55: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==18132== by 0x4008B0: main (noack_segv.c:15)

...

MPI_Comm_rank(comm, &rnk); A = calloc(1, sizeof(uint64_t)); C = calloc(2, sizeof(uint64_t)); A[0] = rnk + 1;

MPI_Allgather(A, 1, MPI_UINT64_T, C, 1, MPI_UINT64_T, comm);

Your 'buf count tuple' is ok for A: every process sends one uint64

your 'buf count tuple' is too small for C if there are any more than 2 proceses .

When you say "more than one"... do you mean 2?

==rob

_______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss

-- Jeff Hammond [email protected] http://jeffhammond.github.io/

_______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss

_______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss