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Subject: Charm++ parallel programming system

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Re: [charm] problem with charm++ freezing


Chronological Thread 
  • From: Olivier Demengeon <olivier.demengeon AT inria.fr>
  • To: Phil Miller <mille121 AT illinois.edu>
  • Cc: charm AT cs.uiuc.edu
  • Subject: Re: [charm] problem with charm++ freezing
  • Date: Tue, 20 Jul 2010 18:36:32 +0200
  • List-archive: <http://lists.cs.uiuc.edu/pipermail/charm>
  • List-id: CHARM parallel programming system <charm.cs.uiuc.edu>

Hello,

Phil Miller wrote:
On Tue, Jul 20, 2010 at 06:08, Olivier Demengeon
<olivier.demengeon AT inria.fr>
wrote:
Hello,

I hope i post this mail at the right place, i look for help on charm++
freezing.

I have a problem with charmrun freezing when gathering cpu tolopology.

I use namd (2.7b3) on IB with charm++. I have a cluster with 32 nodes. Each
nodes have 8 cores.
Is your charm++ build 'net-linux-x86_64-ibverbs' then?

It seems so, it's charm++ provides by namd 2.7b3 IB version
When I use 11 nodes or less, asking 8 process per node everything work fine.
When i try to use more than 11 nodes, still asking 8 process per compter,
charmrun start to sometime hang at gathering cpu topology. More I have node,
more the chance of freeze increase.

Here the commande line I use for 11 nodes :
/charmrun ++verbose +p88 ++nodelist nodes ++scalable-start ++batch 2
./namd2<file>
Could you post the output of this command to the list? Could you also
try it without the "++batch 2" argument? For 32 nodes, no batching
should be needed.

I have used batching, because i had some timeout when too much ssh connection was used
Also, does your cluster have MPI installed, and if so what
implementation? A recent feature in Charm++, included with NAMD 2.7b3,
allows use of some MPI system's startup process to launch Charm++
programs.

Phil


Thx a lot for you answer,
Best regards,
Olivier Demengeon

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