[Wrf-users] Trying to run wrfpost.exe on multiple cores

[Don Morton]

The appended is a post I made to the WRF Users Forum on 08 June.  The
absence of replies there suggests nobody loves me on that forum, so I'll try
another :)

Since the time of my post, I've also compiled this (using mpif90, etc.) on a
Penguin Computing cluster of Opteron processors, and am running in the same
problem.  I've also removed the "PBS Script" interface and am simply using
PBS to grab an interactive node, then running ./run_wrfpost straight from
the command line.  My questions are

1) Are any of you actually running wrfpost.exe in parallel?
2) Are there any "gotchas" I might want to be aware of before digging in
deeper?

Thanks for any help,

Don Morton
Arctic Region Supercomputing Center

-- 
Arctic Region Supercomputing Center
http://www.arsc.edu/~morton/

============================================================

Howdy,

After a fair amount of compilation struggles, I managed to compile the dmpar
version of wrfpost.exe, and am now trying to run wrfpost.exe on a Cray XT5
by inserting the following command line in run_wrfpost:

aprun -n 8 ${POSTEXEC}/wrfpost.exe < itag > wrfpost_${domain}.$fhr.out 2>&1

Then, I have run_wrfpost called by a PBS script which allocates 8 cores.
Although it does execute, what I get for output looks something like:

 we will try to run with 1 server groups
we will try to run with 1 server groups
*** you specified 0 I/O servers
we will try to run with 1 server groups
we will try to run with 1 server groups
CHKOUT will write a file
*** you specified 0 I/O servers
*** you specified 0 I/O servers
CHKOUT will write a file
CHKOUT will write a file
The Posting is using 1 MPI task
There are 0 I/O servers
The Posting is using 1 MPI task
The Posting is using 1 MPI task
There are 0 I/O servers
There are 0 I/O servers
*** you specified 0 I/O servers
CHKOUT will write a file
The Posting is using 1 MPI task
There are 0 I/O servers
0

So, the 8 tasks are launched but

a) Task 7 does not appear to take on the role of an I/O server(the latest
WRF-ARW user's guide seems to imply that it should?)
b) It appears that each task is only aware of itself, and not the other
tasks.

The code actually runs, but takes 9 minutes (1049x1049x51 gridpoints)
whether I use 4 or 8 tasks.

There are plenty of things I might be doing wrong, and I'm preparing to jump
into sorc/wrfpost/SETUP_SERVERS.f to start some tracing, but before I get in
too deep, I'm just wondering if anyone else out there has experience in this
area and is aware of any "gotchas" that might save me a day or two!

I'm literate in MPI and such, so don't really need a lesson in that aspect.
If I have to, I'll try to figure out why the call to mpi_comm_size() seems
to be returning 1 for npes, rather than 8.
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