Re: [BProc] Clustermatic and MPI

[Nicholas H. <he...@se...>]

Thanks!! This makes much more sense... and it works nicely without having
to execute from the master node. I am taking a month off for semester
break, so I will check for your mpirun script when I get back.

Thanks a ton-- keep up the good work. It is nice to see bproc based stuff
without seeing it based specifically on Scyld.

Nic

On Mon, 17 Dec 2001, Erik Arjan Hendriks wrote:

[SNIP]
>
> We saw that here and ended up making our own little modification.
> Attached below is the MPICH patch.  The down side is you need a
> special MPI run to use this.  Unfortunately since that's a separate
> piece of code that I wrote from scratch here, there's a procedure to
> do through to release that.
>
> It's a very simple program though.  Somebody could rewrite it a LOT
> faster than I can get it released if they're feeling impatient.
>
> The patch just creates a new "external execer" facility.  For the
> program "app" and -np 4, mpirun would fork and bproc_execmove the
> following:
>
> rank 0: app -p4execer 0 4 n-1 45541 ;n5,0;n6,1;n7,1;n10,1
> rank 1: app -p4execer 1 4 n5 41922
> rank 2: app -p4execer 2 4 n5 41922
> rank 3: app -p4execer 3 4 n5 41922
>
> -p4execer is the magic argument and it works like this:
>
> for rank 0:
> -p4execer rank jobsize mpirunhost mpirunport procgroup
>
> for rank 1+:
> -p4execer rank jobsize rank0host rank0port
>
> The reason rank 0 is special is because it is the job that all the
> others must connect to in MPI_Init.  In order to do that the others
> must know what host and port rank 0 is on.  mpirun won't know what
> port to tell the others unless rank 0 tells it.  That's why rank zero
> connects to mpirun and sends its port number.  Then mpirun can start
> all the other jobs with approprate arguments.
>
> The format of the process group argument is:
>
> ;host0,0;host1,1;host2,1;host3,1
>
>
> You could just wait for me to get our simple mpirun released but it
> probably wont be for a while since I probably can't do it before xmas
> and the lab is closed for a week then.
>
> - Erik
>

-- 
Nicholas Henke
Undergraduate - SEAS '02
Liniac Project - University of Pennsylvania
http://clubmask.sourceforge.net
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