Charm++ parallel programming system

[Phil Miller <mille121 AT illinois.edu>]

You'll need to add a flag "+p N", where N is the number of actual worker threads the runtime should use - by default, when run as a standalone command from the shell, it will occupy only one.

On the multicore build, this will work directly. On the other builds, you'll need to use our multi-process launcher, charmrun, or pass an additional '+ppn M' flag to indicate a number of threads to run in each process.

See the relevant manual section for details:

http://charm.cs.illinois.edu/manuals/html/charm++/C.html

On Thu, May 18, 2017 at 4:54 PM, Chris Wailes <chris.wailes AT gmail.com> wrote:

First, I'd like to thank everyone for their hard work on the Charm++ project.  My life would be a lot more complicated right now without all of your efforts.

Now, to get to the issue I'm having:

I'm attempting to work with Charm++'s load balancing infrastructure.  Right now, I'd like to develop things on my workstation, which has a single quad-core, hyperthreaded CPU in it.

I've compiled Charm++ with the following versions:

• multicore-linux64
• net-linux-x86_64-smp
• net-linux-x86_64
• netlrts-linux-x86_64-smp
• netlrts-linux-x86_64

I've tried running lb_test, jacobi3d, and kNeighbor with each of these versions using the following commands:

• ./lb_test.every +isomalloc_sync +balancer GreedyLB +LBDebug 9 +LBPrintSummary 1024 100 10 10 100 100 mesh2d
• ./jacobi3d +isomalloc_sync +balancer GreedyLB +LBDebug 9 +LBPrintSummary 128 32
• ./kNeighbor +isomalloc_sync +balancer GreedyLB +LBDebug 9 +LBPrintSummary 128 16 32

So far none of these combinations have resulted in any load balancer summaries or debugging prints besides the following (this output was from the netlrts-linux-x86_64 version):

CharmLB> Verbose level 9, load balancing period: 0.5 seconds
CharmLB> Topology torus_nd_5 alpha: 3.500000e-05s beta: 8.500000e-09s.
CharmLB> Load balancer print summary of load balancing result.
CharmLB> Load balancer assumes all CPUs are same.
Charm++> Running on 1 unique compute nodes (8-way SMP).
Charm++> cpu topology info is gathered in 0.011 seconds.
[0] GreedyLB created

It seems like the line `Running on 1 unique compute nodes (8-way SMP).` might indicate that the load balancer isn't running because there is only 1 "node" or processing element.  I tried and failed to find any way to force the creation of 8 processing elements for my 8 logical cores.

Cold anyone tell me what I need to do to get the load balancer firing when I run these applications on my workstation?

- Chris