* Error when launching MPI applications

	This is usually caused by whether remote nodes are "reachable"
	without typing "password." In your everyday life, if you ssh to
	a node, and always required password, this may be a "big" trouble 
	for MPI applications. See http://www.open-mpi.org/faq/?category=rsh
	for how to set up your ssh. Also, http://www.funtoo.org/wiki/Keychain
	is a good starting point to set up ssh with the "keychain" utility
	under Linux.

* "mca_btl_tcp_frag_recv: readv failed: Connection timed out" when using MPI applications

	This is a strange error, but you can try this patch against the open-mpi which will
	force open-mpi to re-reading buffer again, even after timeout.

*** ompi/mca/btl/tcp/btl_tcp_frag.c.org	2012-04-03 23:30:11.000000000 +0900
--- ompi/mca/btl/tcp/btl_tcp_frag.c	2013-05-02 10:43:21.571867286 +0900
***************
*** 201,206 ****
--- 201,207 ----
  	switch(opal_socket_errno) {
  	case EINTR:
  	    continue;
+ 	case ETIMEDOUT:
  	case EWOULDBLOCK:
  	    return false;
  	case EFAULT:
