Charm++ parallel programming system

[Marius Micluta <marius AT biochim.ro>]

Hi Filippo,

Thank you for clarifying the fact that an SMP build of charm++ is incompatible 
with charmdebug. I also tested the offending command with the precompiled 
non-SMP binary before posting my previous message and it didn't crash, but I 
did not run further a debug session, as my concern is with the SMP version.

however, if charmdebug is not appropriate for my situation, how could I find 
and eliminate the cause of the freeze at startup, which occurs from time to 
time when running the net-linux-x86_64-smp-icc version of charm++/NAMD? The 
NAMD documentation states that "Additional performance may be gained by 
building NAMD against an SMP version of Charm++ such as net-linux-smp or 
net-linux-smp-icc. This will use a communication thread for each process to 
respond to network activity more rapidly." I also found that the SMP build is 
significantly faster than the net-linux-x86_64-icc version. The problem is that 
sometimes it just fails to start properly. On the other hand, when the startup 
succeeds, it runs fine and exits gracefully.

The NAMD documentation is somewhat obscure to me when referring to clusters of 
SMP machines. Besides, it addresses older hardware - single-core dual-processor 
and single hyperthreaded processor architectures. Should I run fewer 
processes/threads per node than the number of available CPU cores?


Sincerely,

Marius