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<TITLE>FW: MPICH, malloc, and my impending assault of one (1) beowulf cluster</TITLE>
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<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: Chris Richard Adams </FONT>
<BR><FONT SIZE=2>Sent: Thursday, August 02, 2001 12:38 PM</FONT>
<BR><FONT SIZE=2>To: 'mundy erik'</FONT>
<BR><FONT SIZE=2>Subject: RE: MPICH, malloc, and my impending assault of one (1) beowulf</FONT>
<BR><FONT SIZE=2>cluster</FONT>
</P>
<BR>
<P><FONT SIZE=2>Hi Erik - </FONT>
</P>
<P><FONT SIZE=2>Admiting your abusiveness is the first and hardest step toward healing..congratulations! I don't have a response to your problem, but perhaps will run into that soon. Unfortuately I am just trying to get the pi code to run. If I may ask...</FONT></P>
<P><FONT SIZE=2>1) did you use the example that comes with the beowulf install - found in \usr\mpi-beowulf\examples? That directory has a pi example, but I can't get the Make to work. Did you succeed? Can I just run MpiCC -o pisamp cpi.c?</FONT></P>
<P><FONT SIZE=2>2.) DO you know of any documentation for those examples, or perhaps could you share a reference to an MPI example. I know C, but nothing about MPI and just want some hello world examples. </FONT></P>
<P><FONT SIZE=2>Thanks,</FONT>
<BR><FONT SIZE=2>Chris</FONT>
</P>
<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: mundy erik [<A HREF="mailto:erik.mundy@HAMPTONU.EDU">mailto:erik.mundy@HAMPTONU.EDU</A>]</FONT>
<BR><FONT SIZE=2>Sent: Wednesday, July 18, 2001 4:35 PM</FONT>
<BR><FONT SIZE=2>To: 'beowulf@beowulf.org'</FONT>
<BR><FONT SIZE=2>Subject: MPICH, malloc, and my impending assault of one (1) beowulf</FONT>
<BR><FONT SIZE=2>cluster</FONT>
</P>
<BR>
<P><FONT SIZE=2>Hello, my name is Erik, and I am an MPICH abuser.</FONT>
</P>
<P> <FONT SIZE=2>I am running a simple one master, two slave Beowulf test cluster,</FONT>
<BR><FONT SIZE=2>RHL 6.1, kernel 2.4.4, MPICH 1.2.1, NFS mount from master to slave on old</FONT>
<BR><FONT SIZE=2>PII 400's. MPICH is giving me some serious headaches - every MPI program I</FONT>
<BR><FONT SIZE=2>execute with a malloc in it crashes with the good old "p4 error: interrupt</FONT>
<BR><FONT SIZE=2>SIGSEGV: 11" message. I have been experimenting with the test programs that</FONT>
<BR><FONT SIZE=2>come with MPICH for simplicity; for example, 'cpi' runs well on all three</FONT>
<BR><FONT SIZE=2>computers. It</FONT>
<BR><FONT SIZE=2>calculates pi, and I rejoice. Mpptest also works without a problem between</FONT>
<BR><FONT SIZE=2>any two of the three computers. But when I try to mpirun "sendrecv" or</FONT>
<BR><FONT SIZE=2>"overtake" from examples/test/pt2pt (both of which use a malloc), MPICH</FONT>
<BR><FONT SIZE=2>gives it the good old college try and then throws me the errors. Normally I</FONT>
<BR><FONT SIZE=2>would just try to do as much as humanly possible to ignore this problem, but</FONT>
<BR><FONT SIZE=2>the code that this beowulf was designed for works when I execute it on one</FONT>
<BR><FONT SIZE=2>computer, and crashes rather spectacularly with the segmentation violation</FONT>
<BR><FONT SIZE=2>error when I try to mpirun it, even on just one computer, leading me to</FONT>
<BR><FONT SIZE=2>think that there is some sort of conflict between MPICH and malloc. </FONT>
<BR> <FONT SIZE=2>Granted, these computers aren't exactly state-of-the-art - each has</FONT>
<BR><FONT SIZE=2>only 128M ram with ~400M swap. But that should be more than enough to</FONT>
<BR><FONT SIZE=2>execute those simple examples. Has anyone had trouble with the Linux</FONT>
<BR><FONT SIZE=2>version of malloc in the past in a situation like this? If you shudder when</FONT>
<BR><FONT SIZE=2>you hear the words "malloc" and "MPICH" used in the same sentence, please</FONT>
<BR><FONT SIZE=2>email me back. This might be a bit difficult to track down, and I'm really</FONT>
<BR><FONT SIZE=2>not the best man for the job, all I did was build a beowulf :). I've only</FONT>
<BR><FONT SIZE=2>been on this list for the last two months but it's taught me that if anyone</FONT>
<BR><FONT SIZE=2>can help its probably you guys. I am EXTREMELY appreciative of any</FONT>
<BR><FONT SIZE=2>assistance you can offer. </FONT>
</P>
<P><FONT SIZE=2>Thanks,</FONT>
</P>
<P><FONT SIZE=2>Erik </FONT>
<BR><FONT SIZE=2>erik.mundy@hamptonu.edu</FONT>
</P>
<P><FONT SIZE=2>PS - also, I should mention that yes, the code I am trying to run WAS</FONT>
<BR><FONT SIZE=2>designed for use with MPI, and yes, I did patch MPICH with the bug fixes</FONT>
<BR><FONT SIZE=2>from the Argonne page. Sorry to take the obvious 'he's so dumb!' solutions</FONT>
<BR><FONT SIZE=2>away... I'm hoping there's one more that maybe I'm just missing :) </FONT>
</P>
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