[mpich-discuss] modifying the round-robin

[Benjamin Svetitsky]

Thanks, the -1 option indeed gets all 4 processes to run on nodeB.  But 
then if I start another -n 4 job, it goes to nodeB as well.  Is there a 
way to get mpd to do load balancing here (namely to send all 4 to the 
next node in line) without specifying the node in the mpiexec command?

		Ben

Rajeev Thakur wrote:
> 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
>>

-- 
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