[mpich-discuss] Modifying ssh calls for MPICH2

[Jed Brown]

On Tue, Jan 17, 2012 at 16:02, Reuti <reuti at staff.uni-marburg.de> wrote:

> main(int argc, char **argv)
> {
>   int node;
>
>   int i,j;
>   float f;
>
>   MPI_Init(NULL,NULL);
>   MPI_Comm_rank(MPI_COMM_WORLD, &node);
>
>   printf("Hello World from Node %d.\n", node);
>       for(j=0; j <= 100000; j++)
>           for(i=0;i <= 100000; i++)
>               f=i*2.718281828*i+i+i*3.141592654;
>

Well this is an odd spin loop because the compiler will happily remove it
for you (note that MPICH2's mpicc wrapper very frequently has optimization
flags in it). I would suggest sleep(3) instead, or, if you must, force the
loop to actually be executed (e.g. seed the loop with the rank and use the
result).
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/mpich-discuss/attachments/20120117/bdcf421e/attachment.htm>