[mpich-discuss] specifying machinefile for MPI_Comm_spawn

[Rajeev Thakur]

Can you try the 1.3 alpha release with the new hydra process manager
(the default)? It should spawn new processes in the order of machines in
the machines file.
 
Rajeev


  _____  

From: mpich-discuss-bounces at mcs.anl.gov
[mailto:mpich-discuss-bounces at mcs.anl.gov] On Behalf Of Jitendra Kumar
Sent: Thursday, April 08, 2010 10:20 AM
To: mpich-discuss at mcs.anl.gov
Subject: [mpich-discuss] specifying machinefile for MPI_Comm_spawn


No, the processes seems to be starting all over on the cluster
irrespective of information in machinefile I used to start the parent
process. I am using MPD.

Although I am using a older version 1.0.8. Can that be a problem?



I want to have a way to specify the hosts directly to MPI_Comm_spawn. I
was able to do that using key 'host' but that allows me to specify one
node only. I tried specifying multiple nodes using 'hosts' but that
didn't work.

Are the supported info keys listed/documented somewhere?



Thanks,

Jitu



I am not sure if a machinefile info key to MPI_Comm_spawn is currently

supported, but new processes should be spawned on hosts in the order in

the machinefile used to start the job. Is that not what you are seeing?

Are you using MPD or hydra?



Rajeev

 



> -----Original Message-----

> From: mpich-discuss-bounces at mcs.anl.gov
<https://lists.mcs.anl.gov/mailman/listinfo/mpich-discuss>  

> [mailto:mpich-discuss-bounces at mcs.anl.gov
<https://lists.mcs.anl.gov/mailman/listinfo/mpich-discuss> ] On Behalf
Of Jitendra Kumar

> Sent: Wednesday, April 07, 2010 11:30 AM

> To: mpich-discuss at mcs.anl.gov
<https://lists.mcs.anl.gov/mailman/listinfo/mpich-discuss> 

> Subject: [mpich-discuss] specifying machinefile for MPI_Comm_spawn

> 

> Hi,

> I would appreciate your help with a doubt using MPI_Comm_spawn.

> 

>   In order to specify the target hosts for spawning new child 

> processes 

> through MPI_Comm_spawn call, what is correct "key" value that 

> needs to 

> be set in MPI_Info.

> 

> Normally I always specify the hosts to start the MPI processes, by 

> passing the argument '-machinefile'

> mpiexec -machinefile mf -n np ./program

> 

> However, passing machinefile key through MPI_Info in MPI_Comm_spawn 

> seems to have no effect.

> MPI_Info_set(hostinfo, "machinefile", "mf")

> 

> The spawned processes are getting started on arbitrary nodes on the 

> cluster.

> 

> I tried to set the key "host" through MPI_Info_set(hostinfo, "host", 

> "node2") and it works. But this way I can specify only single 

> host, and 

> is a problem if I am starting MPI_Comm_spawn with large number of 

> processors and wants to have control on where they are started.

> 

> I believe I am missing the correct key to set for MPI_Info 

> for passing 

> the machinefile. Would be a great help if you can provide 

> some pointers.

> 

> Thanks,

> Jitu



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