Newsgroups: comp.parallel.pvm
From: Ingo Reise <reise>
Subject: Re: PVM buffering
Organization: University of Wuerzburg, Germany
Date: 29 Jun 1995 08:46:52 GMT
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Message-ID: <3stp9s$pcc@winx03.informatik.uni-wuerzburg.de>

Hi!

Here is a part of .../pvm-3.3.4/Readme.mp.
The information is given for shared-memory-systems.
Perhaps it could help you to fix your problem.

..
        2. The buffer size used by PVM, SHMBUFSIZE, is defined in
pvm3/src/pvmshmem.h, with a default of 1MBytes. Your message must fit
in the buffer. If your program uses large messages, this parameter MUST
be increased accordingly. Note that the default system limit on shared-
memory segment size (1 MB on Sun's) may have to be raised as well.
A large number of small messages can also fill up the buffer if they
are not received in time, and the performance degrades considerably
when this happens.

        3. You can change the buffer size by setting the environment
variable PVMBUFSIZE before starting PVM. This would have the same
effect as changing SHMBUFSIZE and recompiling PVM.

        4. When a task sends a message to another task, only the pointer
is passed. The receiving task should call pvm_freebuf() to "destroy"
the receive buffer after the data have been unpacked, and allow the
sender to reuse that space.

        5. If you save any PVM buffers (with pvm_setsbuf, for example),
it is important that you free them before calling pvm_exit(), otherwise
your process will hang.
..

Greetings 
Ingo


                     __o           
                     \<,           
___________________()/ ()______________________________________________________
Ingo Reise                                      
Robert-Kirchhoff-Strasse 55    Lehrstuhl fuer Informatik II
97076 Wuerzburg                Universitaet Wuerzburg
Tel. 0931/273597               e-mail: reise@informatik.uni-wuerzburg.de


