Newsgroups: comp.parallel.pvm
From: Marcello-Gianluca <meta@calpar.cnuce.cnr.it>
Subject: Re: PVM install problem...
Organization: Universita' di Pisa
Date: 24 Feb 1995 07:35:21 GMT
Message-ID: <3ik27p$j0q@serra.unipi.it>

dendris@leon.cti.gr wrote:
>
> hi everyone,
>         I just installed PVM 3.3.0 to a SPARCStation 5. I have the following
> problem: My programs, as well as the distribution examples, do not work or
> hang when I try to spawn more than 10 - 12 processes (i.e spmd.c when
> compiled with NPROCS = 10, starts but hangs...)
> 
>         Is there anything to do? I tried to increase the available file
> descriptors to 256, (so that the pvmd will be able to create the necessary
> sockets) but to no avail... Every idea would be more than welcome.
> 
Perhaps, the problem is due to the limit on the number of TCP 
connections. By default, PVM tries to establish direct TCP connections
between communicating processes. If PVM reaches the limit, the program
hangs. We had a similar problem on an IBM SP1.

You could try to insert;

  pvm_setopt(PvmRoute, PvmDontRoute);

just after pvm_mytid() in spmd.c. This will avoid creating a direct 
TCP connection between communicating processes.

Hope this help,
Gianluca

--
   /| /|+-----+--|\     Gianluca Faieta & Marcello Formica
  / |/ ||__   |  | \    Tesi Metacomputer
 /     ||     |  |__\
/      |+---  |  |   \  E-mail: meta@calpar.cnuce.cnr.it


