Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |  

This web mail archive is frozen.

This page is part of a frozen web archive of this mailing list.

You can still navigate around this archive, but know that no new mails have been added to it since July of 2016.

Click here to be taken to the new web archives of this list; it includes all the mails that are in this frozen archive plus all new mails that have been sent to the list since it was migrated to the new archives.

From: Ralph H Castain (rhc_at_[hidden])
Date: 2006-06-30 09:08:45

Hi Amrita

I¹m not entirely sure I understand your questions, but will try to answer
them below. If you can share what you are doing, we¹d be happy to provide


On 6/30/06 5:45 AM, "amrita mathuria" <amrita_mathuria18_at_[hidden]> wrote:

> hi...
> I am working with open mpi source code....
> I want to know what is the role of daemons in the whole process...

Generally, we use the host system's launch capability (rsh, ssh, SLURM,
etc.) to launch a daemon on every node that will be used for a job. The
daemons are then instructed to launch the application's processes on their
local node.

> After mpirun launches the daemons and daemons launches the process on
> different nodes.....

Daemons are used to forward I/O between mpirun and the application
processes, and also monitor the state of the processes they launched. In
this latter case, the daemons specifically alert mpirun to abnormal
terminations. Other than that, the daemons don't really do anything after

> And also do the mpirun interacts with the daemons after launching them....or
> it directly interact with the processes when there is a need....?????

Mpirun always interacts directly with the processes. The only exception is
when mpirun needs to order termination of the entire job (e.g., if the user
issues a ctrl-C) - in this case, the daemon can be ordered to "kill" the
local process.
> thanks
> Amrita
> Want to be your own boss? Learn how on Yahoo! Small Business.
> <*>
> _______________________________________________
> devel mailing list
> devel_at_[hidden]