Hi Changsheng<br><br>Thank you very much for your solution. The program runs well now :)<br><br>Regards.<br><br><div class="gmail_quote">On Tue, Apr 20, 2010 at 3:54 PM, Changsheng Jiang <span dir="ltr">&lt;<a href="mailto:jiangzuoyan@gmail.com">jiangzuoyan@gmail.com</a>&gt;</span> wrote:<br>

<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">I have encountered the same problem too. <br><br>By gdb attached, it&#39;s show that the processes are in a loop of (e)poll. After configuring the network interface in ~/.openmpi/mca-params.conf using btl_tcp_if_include, all hosts work fine.<br>



<br>just fyi.<br clear="all">                                                      Changsheng Jiang<br>
<br><br><div class="gmail_quote"><div><div></div><div class="h5">On Tue, Apr 20, 2010 at 14:39, long thai <span dir="ltr">&lt;<a href="mailto:thaithanhlong2501@gmail.com" target="_blank">thaithanhlong2501@gmail.com</a>&gt;</span> wrote:<br>

</div></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div></div><div class="h5">

<p>Hi all.</p>

<p>I&#39;m just using OpenMPI for few days. I&#39;ll try to run a simple MPI 
program, the program is ProcessColors which I get from <a href="http://ci-tutor.ncsa.illinois.edu/content.php?cid=1091" rel="nofollow" target="_blank">CI-Tutor</a>. I have 2 hosts, if I run the program 
separately on each one, it runs well. However, if I run it on two hosts 
using following command: <b>mpirun --host host1,host2 
--preload-binary -np 8 ProcessColors</b>. The program hangs.</p><p>When I use command <b>ps -A</b> to check running process, I 
find out that there is 4 processes running on each host. So, I think 
that there is a deadlock on my program, but why it runs well with single
 host?</p><p>All those following commands run without any problem on both machine:</p>

<ul><li>mpirun -np 8 ProcessColors</li><li>mpirun --host host1 -np 8 ProcessColors</li><li>mpirun --host host2 -np 8 ProcessColors</li></ul>Later, I found out that the problem comes when the remote host try to send message to the host which root process (process 0) is running, which is the host that I run the command. I don&#39;t know why the process is blocked at sending task.<br>





<p>Any help from you is precious to me.</p>

<p>Regards.</p>

<p>Long Thai.</p><font color="#888888"><br>
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