Newsgroups: comp.parallel.pvm
From: subraman@cs.iastate.edu (Krishnan Subramaniam)
Subject: Re: Is PVM Thread Safe?
Organization: Iowa State University, Ames, Iowa
Date: 1 Jun 95 17:32:25 GMT
Message-ID: <subraman.802027945@shazam.cs.iastate.edu>

"Lawrence L. Chan" <lchan> writes:

>Hi,

>We're currently using PVM 3.3.7 to develop a parallel query execution
>engine running in a network of SUN workstations environment.  We'd
>like to know if PVM is Thread-Safe with Solaris2.4 threads.

>Thank you very much in advance.

>Lawrence Chan
>lchan@cs.ucla.edu

Hi Lawrence,
	I doubt if you can easily thread PVM 3.3.7 as there are many
places in the code where the message list is updated or free buf list
is updated so if two diff threads access these lists non-atomically
it could result in bugs that are DIFFICULT to spot. You might consider
mutex-ing the access to these lists and also the buffer mgmt code as PVM
allocates memory as and when it needs it and keeps recycling memory so
once again 2 independent threads which each call say mkbuf or initsend
could result in unpredictable results or crashes.
	So in a word NO pvm 3.3.7 is not thread safe if more than one
thread is going to use pvm functions.

Hope that helps,

Sincerely ,
Krishnan.
--
Krishnan R Subramaniam
Voice Mail : 515 - 296 4209.
Email	   : subraman@cs.iastate.edu   
HTML  	   : http://www.public.iastate.edu/~rsk/

