openmpi loses output across multiple nodes

Eric Shamay eric.... at gmail.com
Tue Jul 22 23:41:47 CEST 2008


Axel,

Which program (mpi or cp2k) are you asking about verbosity? On both I
leave the defaults set and both behave as expected when running on a
single node. I tried the extra '-v' switch, and also using the '-i
<input file> -o <output>'  also without any luck.




On Jul 22, 5:06 pm, Axel <akoh... at gmail.com> wrote:
> On Jul 22, 4:46 pm, Eric Shamay <eric.... at gmail.com> wrote:
>
>
>
> > Hello all,
>
> > I've succeeded in compiling the parallel cp2k, and have run the
> > benchmarks included (as well as my own simulations) to satisfy myself
> > that indeed all is as it seems. Everything works fine when running on
> > a single node.
>
> > When running on 2 processors on a single node I issue:
>
> > mpirun -np 2 cp2k.popt <input file>
>
> > all is well. Output looks fine and the cpus are both running at 100%.
>
> > When trying to run the program on 2 nodes (identical hardware and
> > software setup) I run into a problem. I have a host file for openmpi
> > that lists the processors, 2 cpus per node, and the networking seems
> > to be fine. I issue the command:
>
> > mpirun -np 4 -machinefile ~/hostfile cp2k.popt <input file>
>
> > and the 4 processes seem to fire up just fine: 2 processes per node
> > are running and all 4 processes use 100% of each cpu. However, I don't
> > have any output from cp2k. It seems as though the head node that runs
> > the mpirun command just gets all the processors running but can no
> > longer speak to stdout or do any type of I/O.
>
> eric,
>
> how verbose is your output? it may be switched to buffered mode
> (4k) for performance reasons. try the -i and -o flags for input
> and output.
>
> cheers,
>    axel.
>
> > I'm not sure if this is a common problem but I'm at a loss as to
> > searches in the man pages, documentation, and on the forum and on
> > google, etc. Does anyone know what might be happening?
>
> > Thanks,
> > ~Eric


More information about the CP2K-user mailing list