Charm++ parallel programming system

["Kale, Laxmikant V" <kale AT illinois.edu>]

I have a feeling that the underlying MPI implementation is running out of
some resource (#messages or buffer space).

What machine are you running on? How many nodes?

A good solution is to link in the TRAM library (but its experimental, and
under development) that automatically combines messages to reduce their
number. 

It may be good to break the loop down into two levels: send a few hundred
messages, then send a single message to yourself to continue the process.
This way, you give a chance to the runtime system to call the MPI progress
engine. 

‹ Sanjay

On 10/3/14, 4:46 PM, "Robert Steinke" 
<rsteinke AT uwyo.edu>
 wrote:

>I'm having a problem with my charm application.
>
>Before I get into the problem, I tried to use the ccs_tools charm
>debugger, but haven't been able to yet.  I read in the manual that it
>only works for net-* versions of charm, and I am running on an mpi-*
>version.  The process of getting my code to run on a net-* version
>started to turn into a real mess.  For example I'm using the parallel
>version of the NetCDF library that requires MPI.  I could probably get
>it running on a net-* version, but my first question is whether that's
>the right road to be going down. Is it likely the ccs_tools debugger
>will be useful for solving this problem, or is there something else I
>can do?
>
>Here's the problem:
>
>In an entry method of one object I have a loop that sends out messages
>to every element of a chare array.  I'm sending an individual message to
>each object in a loop, not a broadcast through the array proxy, because
>I need to send different parameters to each object.  Like this:
>
>for (ii = 0; ii < proxySize; ii++)
>{
>   proxy[ii].message(parameters[ii]);
>}
>
>When proxySize is large and I send a lot of messages (about 37,000) a
>couple percent of them never arrive.  The missing messages are scattered
>around the array.  When I send a small number of messages they all arrive.
>
>Has anyone experienced something like this before?
>
>I was hoping that the ccs_tools debugger would be able to do things like
>show me the queued messages so I can see messages being sent and
>received so I can tell if this is really a problem with charm not
>delivering messages or if I'm doing something wrong.  Is this something
>that ccs_tools could show me?
>
>Thanks for the help,
>
>Bob Steinke
>
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