[mpich-discuss] modifying the round-robin

[Rajeev Thakur]

Since you are running from node C, MPD will place the first process on node
C by default. You can turn that feature off with the "-1" option to mpiexec.

Rajeev 

> -----Original Message-----
> From: mpich-discuss-bounces at mcs.anl.gov 
> [mailto:mpich-discuss-bounces at mcs.anl.gov] On Behalf Of 
> Benjamin Svetitsky
> Sent: Wednesday, December 10, 2008 2:41 AM
> To: mpich-discuss at mcs.anl.gov
> Subject: [mpich-discuss] modifying the round-robin
> 
> Greetings,
> 
> I am running MPICH2 on a cluster of four quad-core machines 
> under Linux. 
>   If I run a job such as
> 
> mpiexec -l -n 4 hostname
> 
> then one process runs on each node, whereas I would prefer 
> that all four run on the same node.  I tried modifying 
> mpd.hosts to read:
> 
> nodeA:4
> nodeB:4
> nodeC:4
> nodeD:4
> 
> but the result is not what I expected:
> 
> nodeC% mpiexec -l -n 4 hostname
> 0: nodeC
> 3: nodeB
> 2: nodeB
> 1: nodeB
> 
> How can I get the mpd to fill the hosts one by one reliably?
> 
> Incidentally, the :4 option is not documented in the 
> Installation Guide. 
>   I picked it up in the gutter.  If it doesn't do this, what 
> DOES it do?
> 
> Thanks,
> 	Ben
> -- 
> Prof. Benjamin Svetitsky         Phone:            +972-3-640 8870
> School of Physics and Astronomy  Fax:              +972-3-640 7932
> Tel Aviv University              E-mail:      bqs at julian.tau.ac.il
> 69978 Tel Aviv, Israel           WWW: http://julian.tau.ac.il/~bqs
>