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Subject: Charm++ parallel programming system

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Re: [charm] migrate non array chares


Chronological Thread 
  • From: Nicolas Bock <nicolasbock AT gmail.com>
  • To: Jonathan Lifflander <jliffl2 AT illinois.edu>
  • Cc: "charm AT cs.uiuc.edu" <charm AT cs.uiuc.edu>
  • Subject: Re: [charm] migrate non array chares
  • Date: Mon, 22 Jul 2013 11:39:24 -0600
  • List-archive: <http://lists.cs.uiuc.edu/pipermail/charm/>
  • List-id: CHARM parallel programming system <charm.cs.uiuc.edu>

Suppose I have two chare arrays, A and B. Both contain data, and I would like A to do some computation and B to only provide data to A and not compute anything itself. Will the load balancer consider both arrays for migration? Will it try to move the data in B close to the work in A?

Thanks,

nick



On Sat, Jul 20, 2013 at 9:54 AM, Jonathan Lifflander <jliffl2 AT illinois.edu> wrote:
Normal chares in Charm++ are not load balanced like an array (which is
something we intend to change eventually). Instead, we use "seed"
balancers to load balance them. See manual section
http://charm.cs.illinois.edu/manuals/html/charm++/7.html#SECTION01670000000000000000

Singleton chares in Charm++ are typically viewed as a "task", which
will do some work (probably a fairly small amount), and then possibly
spawn some children chares. Hence, the seed load balancer for them
just moves the seed around, which is essentially a creation message.
So they can be migrated or load balanced until they are actually
instantiated. Once creation occurs, they are fixed on a processor.

For iterative applications, or ones where the parallelism is more
structured, we would recommend that you use a chare array. Note that
chare arrays allow dynamic insertions, which allows the size of the
collection to asynchronously grow at runtime.

On Fri, Jul 19, 2013 at 4:58 PM, Nicolas Bock <nicolasbock AT gmail.com> wrote:
> Hi,
>
> can normal chares, i.e. one I declare "chare Something" in the interface
> file be migrated? Can they be load balanced?
>
> Thanks,
>
> nick
>
>
> _______________________________________________
> charm mailing list
> charm AT cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/charm
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