[mpich-discuss] MP_EAGER_LIMIT and MP_BUFFER_MEM question

[Jeff Hammond]

Unless you're on a BGQ or IBM machine with LoadLeveler, I don't see
how those variables can have any impact on the execution of your code.

cc:mpich2-trunk jhammond$ grep MP_EAGER_LIMIT * -R
src/mpid/pamid/src/mpidi_env.c:    char* names[] = {"PAMID_EAGER",
"PAMID_RZV", "MP_EAGER_LIMIT", "PAMI_RVZ", "PAMI_RZV", "PAMI_EAGER",
NULL};
src/mpid/pamid/src/mpidi_env.c:    char* names[] = {"PAMID_RZV_LOCAL",
"PAMID_EAGER_LOCAL", "MP_EAGER_LIMIT_LOCAL", "PAMI_RVZ_LOCAL",
"PAMI_RZV_LOCAL", "PAMI_EAGER_LOCAL", NULL};
src/mpid/pamid/src/mpidi_util.c:
MATCHI(eager_limit,"Message Eager Limit (MP_EAGER_LIMIT/Bytes):");
src/pm/hydra/tools/bootstrap/external/ll_env.c:
"MP_DEBUG_INITIAL_STOP", "MP_DEBUG_LOG", "MP_EAGER_LIMIT",

Can you provide a test code that exercises the problem to which you allude?

Thanks,

Jeff

On Wed, Nov 7, 2012 at 4:53 PM, Matthew Niemerg
<niemerg at math.colostate.edu> wrote:
> Hello,
>
> I'm developing a parallel program and have run into MPI hanging on jobs.
> I've narrowed the problem down to broadcasting data to other nodes.  I am
> curious how to get a hold of and set the environment variables
> MP_EAGER_LIMIT and MP_BUFFER_MEM.  We need to be able to adjust our code
> based off of individual machine's configurations of MPI, which is why I need
> to get what the environment variables are.  I tried to use the
> getenv("MP_EAGER_LIMIT") call, but that seemed to fail.  In addition, I've
> tried to set these environment variables using the export command in the
> shell before running my program, but that doesn't seem to work either.
>
> Are these environment variables set at runtime, during the configuration of
> mpich2, or what?  The data that is being passed is about 10 megs, which, I
> wouldn't think would be an issue, but apparently is!
>
> Anyway, any help you can provide would be much appreciative.
>
> Sincerely,
> Matthew Niemerg
> Graduate Research Assistant
> Mathematics Department
> Colorado State University
>
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-- 
Jeff Hammond
Argonne Leadership Computing Facility
University of Chicago Computation Institute
jhammond at alcf.anl.gov / (630) 252-5381
http://www.linkedin.com/in/jeffhammond
https://wiki.alcf.anl.gov/parts/index.php/User:Jhammond