It would be difficult to do well without some MPI help, in my
opinion. You certainly could use the Linux processor affinity API
directly in the MPI application. But how would the process know
which core to bind to? It could wait until after MPI_INIT and call
MPI_COMM_RANK, but MPI implem
Ralph,
Thanks for the feedback. Glad we are clearing these things up. :-)
So here's what osc mpiexec is doing now:
---
-pernode : allocate only one process per compute node
-npernode : allocate no more than processes per
compute node
---
> Cdm> I think I originally requested the -pernode
Brian
But does it matter which core the process gets bound to? They are all
identical, and as long as the task is parallelized in equal chunks (that's
the key part), it should not matter. The last time I had to do this, the
problem had to do with real-time processing of a very large radar image.
I agree with this solution, for the machinefile.
Using mpiexec or a spawn command, you can add the cpu number attached to the
hostname :
mpiexec -host [hostname]:[cpu number] -n 1 mpi_test
or, for MPI_Comm_spawn :
MPI_Info_set( mpi_info, "host", "[hostname]:[cpu number]" );
Cheers,
Lau
On Nov 21, 2006, at 1:27 PM, Brock Palen wrote:
I had sent a message two weeks ago about this problem and talked with
jeff at SC06 about how it might not be a OMPI problem. But it
appears now working with myricom that it is a problem in both
lam-7.1.2 and openmpi-1.1.2/1.1.1. Basically the re
There's a few issues involved here:
- Brian was pointing out that AMDs are NUMA (and Intel may well go
NUMA someday -- scaling up to hundreds of cores, unless something
quite unexpected happens in terms of computer architectures, simply
does not scale in UMA architectures). So each core is
The real complexity comes in when trying to schedule on particular
cores in a machine. For example, we discussed some real-world
application examples that wanted to do the following:
- Launch 1 MPI process per socket, pinning all cores on the socket to
that process
- Launch 2 MPI processe
On Nov 29, 2006, at 8:44 AM, Scott Atchley wrote:
My last few runs all completed successfully without hanging. The job
I am currently running just hung one node (can respond to ping,
cannot ssh into it, cannot use any terminals connected to it).
There are no messages in dmesg and vmstat shows t
On Wed, Nov 29, 2006 at 08:48:48AM -0500, Jeff Squyres wrote:
> - There's also the issue that the BIOS determines core/socket order
> mapping to Linux virtual processor IDs. Linux virtual processor 0 is
> always socket 0, core 0. But what is linux virtual processor 1? Is
> it socket 0, cor
Hi Chris
Thanks for the patience and the clarification - much appreciated. In fact, I
have someone that needs to learn more about the code base, so I think I will
assign this to him. At the least, he will have to learn a lot more about the
mapper!
I have no problem with modifying the pernode beha
Ralph,
I agree with what you stated in points 1-4. That is what we are looking
for.
I understand your point now about the non-MPI users too. :-)
Thanks,
-cdm
-Original Message-
From: users-boun...@open-mpi.org [mailto:users-boun...@open-mpi.org] On
Behalf Of Ralph Castain
Sent: Wednesda
We have found a potential issue with BPROC that may effect Open MPI.
Open MPI by default uses PTYs for I/O forwarding, if PTYs aren't
setup on the compute nodes, Open MPI will revert to using pipes.
Recently (today) we found a potential issue with PTYs and BPROC. A
simple reader/writer usin
I cannot get X11 forwarding to work using mpirun. I've tried all of the
standard methods, such as setting pls_rsh_agent = ssh -X, using xhost,
and a few other things, but nothing works in general. In the FAQ,
http://www.open-mpi.org/faq/?category=running#mpirun-gui, a reference is
made to oth
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