Hi,<br> We recently received the following post and we seem to have the<br>same behavior with mpich2-1.5a1. We realize that this is because we are running out<br>of context id's. Do you folks think it is feasible to increase the range of<br>
allowable context id's? <br> <br> <br> The following code can be used to reproduce this behavior: <br><br>---------------------------------------------------------<br><br>#include <mpi.h><br>#include <stdlib.h><br>
<br>int main(int argc, char **argv)<br>{<br> int num_groups = 1000, my_rank, world_size, *group_members, i;<br> MPI_Group orig_group, *groups;<br> MPI_Init(&argc, &argv);<br> MPI_Comm *comms;<br><br> if ( argc > 1 ) num_groups=atoi(argv[1]);<br>
<br> MPI_Comm_rank( MPI_COMM_WORLD, &my_rank );<br> MPI_Comm_size(MPI_COMM_WORLD, &world_size);<br> MPI_Comm_group(MPI_COMM_WORLD, &orig_group);<br><br> group_members = calloc(sizeof(int), world_size);<br>
groups = calloc(sizeof(MPI_Group), num_groups);<br> comms = calloc(sizeof(MPI_Comm), num_groups);<br><br> for ( i = 0; i < world_size; ++i ) group_members[i] = i;<br><br> for ( i = 0; i < num_groups; ++i )<br>
{<br> MPI_Group_incl(orig_group, world_size, group_members, &groups[i]);<br> MPI_Comm_create(MPI_COMM_WORLD, groups[i], &comms[i]);<br> }<br>} <br><br>The observed error is : <br>PMPI_Comm_create(656).........: <br>
MPI_Comm_create(MPI_COMM_WORLD, group=0xc80700f6, new_comm=0x1d1ecd4) failed<br><div id=":21r">
PMPI_Comm_create(611).........:<br>
MPIR_Comm_create_intra(266)...:<br>
MPIR_Get_contextid(554).......:<br>
MPIR_Get_contextid_sparse(785): Too many communicators<br>
[cli_0]: aborting job:</div><br><br><br>Thanks,<br>Krishna<br><br><br><div class="gmail_quote">On Thu, Feb 23, 2012 at 1:32 PM, Lewis Alderton <span dir="ltr"><<a href="mailto:lalderto@us.ibm.com">lalderto@us.ibm.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
I'm using MPI_Group_incl to create many groups. There seems to be limit of<br>
2048 groups - any way to increase this number ?<br>
<br>
( I'm using mvapich2-1.8a1p1 )<br>
<br>
Thanks.<br>
<br>
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</blockquote></div><br>