Newsgroups: comp.parallel.pvm
From: ghogenso@u.washington.edu (Gordon Hogenson)
Subject: Re: Unexpected problems with pvm_spawn and pvm_joingroup
Organization: University of Washington
Date: 28 Jul 1995 16:22:30 GMT
Message-ID: <3vb2s6$ssh@nntp5.u.washington.edu>

ericd@backus (Eric Dye) writes:

>Gordon Hogenson (ghogenso@u.washington.edu) wrote:
>: I'm having some trouble with a new installation of PVM 3.3.7.  I have
>: it installed on two machines, a SUN4 and and SGI5. Specifically,
>: the SGI is an IRIX 5.2 Indigo^2 and the SUN is SunOS 4.1.4. My program
>: (see below) is run (started from the shell prompt) on the SUN4, 
>: and spawns 1 process on the SGI5.

>: The first problem is that pvm_spawn always returns 0 on the first call,
>: (with -7 returned in the tids array), but on the second call it
>: returns 1 as expected and the 'tid' of the spawned task is correct.


>I am fairly new to PVM but I think I am having problems similar to 
>Gordon.  I am running PVM on a SUN4 and SUNMP.  When running the
>example programs several of them worked every other time.  I also
>tried a quicksort.c program which I found on one of the PVM pages.
>It also works every other time.  What I have found is that if
>I only use the SUNMP as my virtual machine then the programs work
>fine.  If the SUN4 is the only machine then they never work (give
>wrong answers on some programs and sometimes lock-up on others).  In most 
>cases I use the same code for both architectures.  How can I find out 
>what's going wrong when running on the SUN4?  Also I am having trouble
>printing inside a spawned task, what is the easiest or best way to
>do this?  Thanks.

With the help of Stuart Blackburn <sdblackb@uncc.edu>, I found the
cause of the problem, and it sounds like ths may also be the cause of
Eric's problem.  I was making the assumption that hello_other always
would be running on the *OTHER* machine, so I didn't compile it on
my own machine.  Stuart mentioned that 'hello' starts up a process
on a random machine in the network, meaning that 'every other time' (when
it tried to start it on the local host) it failed.

Gordon.
-- 
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Gordon J. Hogenson                       work: (505) 667-9471
ghogenso@u.washington.edu                home: (505) 661-6753
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