Newsgroups: comp.parallel.pvm
From: Lisa Nicklas <lnicklas@gmu.edu>
Subject: Using pvm_sendsig()
Organization: George Mason University, Fairfax, Virginia, USA
Date: Sat, 03 Feb 1996 18:09:53 -0500
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Message-ID: <3113EB41.41C67EA6@gmu.edu>

Hi,


   We are having a problem using pvm_sendsig().  

   In our application, we are passing a single message around a logical
ring of tasks.  To avoid having each task constantly use pvm_probe() to
check for the message's arrival, we are using pvm_sendsig() to notify a
task that the message is on its way.  With PvmRoute set to
PvmRouteDirect, we found that this method only worked when there are two
tasks.  For greater than two tasks the program would hang within a call
to pvm_send().  Using a debugger, we found that pvm_send() made a call
to mroute() which made a call to select().  The call to select() would
never return.   

   If we turned PvmRouteDirect off, we found that our application works
sometimes (about a 10% failure rate).  

   Does anyone have any helpfull hints about using signals with PVM
applications?

Thanks alot,
Lisa Nicklas
lnicklas@gmu.edu

