[MPICH] MPI_Bcast hangs in Windows XP

Mon Sep 10 21:27:36 CDT 2007

a) I can ping the other machine from one machine without any problem.
b) Also tried by just specifying ipaddress of hosts in Config.txt and I got the same error message in my previous email.

The issue seems to be caused by the following setting at my end.
i)I got one machine name by using "nslookup ipaddress".(B001279FD7C60.il.bankofamerica.com)
ii)If I right click "My Computer"->Properties->Computer Name, I got the other name(B001279FD7C60.corp.bankofamerica.com).

I wrote a very simple C probelm which just does one thing: call gethostbyname. If I pass hostname from i), the call is successful, and if I pass hostname from ii), I got
exactly the same error message as the MPI error message.

What I don't understand is the following:  even if I specify hostnames(full names) from i) in Config.txt, I still got the same error messages and from the error messages, it seems that
mpiexec does not honor the hostnames I specify in Config.txt, and instead it somehow uses hostnames from ii). Is it a bug in mpiexec?or a bad setting at my end? Or a combination 
of the above two?

Thanks

Richard

From: jayesh at mcs.anl.gov
To: xs_li at hotmail.com
CC: mpich-discuss at mcs.anl.gov
Subject: RE: [MPICH] MPI_Bcast hangs in Windows XP
Date: Mon, 10 Sep 2007 11:54:39 -0500

Hi,
 Also try to ping the hosts by specifying the 
hostname (ping <hostname>).

Regards,
Jayesh

From: owner-mpich-discuss at mcs.anl.gov 
[mailto:owner-mpich-discuss at mcs.anl.gov] On Behalf Of Jayesh 
Krishna
Sent: Monday, September 10, 2007 9:39 AM
To: 
'Richard Li'
Cc: mpich-discuss at mcs.anl.gov
Subject: RE: 
[MPICH] MPI_Bcast hangs in Windows XP

Hi,
 It looks like some problem with the name resolution for the 
hostnames. Can you try one run by just specifying the ipaddress of the hosts in 
config.txt ?

Regards,
Jayesh

From: Richard Li [mailto:xs_li at hotmail.com] 

Sent: Friday, September 07, 2007 9:00 PM
To: Jayesh 
Krishna
Cc: mpich-discuss at mcs.anl.gov
Subject: RE: [MPICH] 
MPI_Bcast hangs in Windows XP

Jayesh,

Thanks a lot for your 
info.

After a lot of trys, I was finally able to run cpi.exe across 
multiple hosts. It seems to have something to with the setting in my machine 
file. The following is the detail.

I use the following command to run 
cpi.exe:

mpiexec -n 2 -machinefile config.txt -channel ssm(or others) 
cpi.exe

a) If I have a config.txt file like the 
following:
    host1name:1 -ifhn 
host1_ipaddress
    host2name:2 -ifhn 
host2_ipaddress
   Everything works fine(for all channels).
b) 
If I have a config.txt like the following:

host1name:1
   host2:name:2
 then, for sock channel, it 
hangs mpi_bcast. For auto and ssm, I got the following error message:

C:\public\bin>mpiexec -n 2 -machinefile Config.txt 
-channel ssm  or auto 
C:\public\bin\cpi.exe
Enter the number of intervals: (0 quits) 
100

job aborted:
rank: node: exit code[: error 
message]
0: B0016350B383E: 1: Fatal error in MPI_Bcast: Other MPI error, 
error stack:
MPI_Bcast(784).................: MPI_Bcast(buf=0012FE88, 
count=1, MPI_INT, root=0, MPI_COMM_WORLD) 
fai
led
MPIR_Bcast(230)................:
MPIC_Send(36)..................:
MPIDI_EagerContigSend(146).....: 
failure occurred while attempting to send an eager 
message
MPIDI_CH3_iStartMsgv(224)......:
MPIDI_CH3I_VC_post_connect(555): 
[ch3:sock] rank 0 unable to connect to rank 1 using business card 
<po
rt=3872 description=B001279FD7C60.corp.bankofamerica.com 
ifname=171.188.32.154 shm_host=B001279FD7C60.
corp.bankofamerica.com 
shm_queue=39E4F281-FCC0-4f4a-B540-EDC8D517F065 shm_pid=2484 
>
MPIDU_Sock_post_connect(1228)..: unable to connect to 
B001279FD7C60.corp.bankofamerica.com on port 387
2, exhausted all endpoints 
(errno -1)
MPIDU_Sock_post_connect(1244)..: gethostbyname failed, The 
requested name is valid and was found in th
e database, but it does not have 
the correct associated data being resolved for. (errno 11004)
1: 
B001279FD7C60: 1
I know this has something to do with my network 
setting, but just can't figure out why.

Any 
ideas?

Thanks

Richard

  From: jayesh at mcs.anl.gov
To: xs_li at hotmail.com
CC: 
  mpich-discuss at mcs.anl.gov
Subject: RE: [MPICH] MPI_Bcast hangs in Windows 
  XP
Date: Thu, 6 Sep 2007 09:25:36 -0500

  Hi,
   The process manager (smpd) is responsible 
  for launching the MPI processes on the various machines and providing an MPI 
  processes information on how to communicate with other MPI 
  processes.
   The SMPD process manager listens (default 
  case) on port 8676 and then asks the client PM to connect to a new port. 
  So you should allow SMPD process manager (smpd.exe --- installed as a service 
  in windows) to communicate at all ports (This is the easiest way. However you 
  can also restrict the port range used by SMPD. Refer to the windows devloper's 
  guide available at http://www-unix.mcs.anl.gov/mpi/mpich/ for 
  details.)
   Make sure that no firewall (1. Running on 
  the individual machines   2. OR on the network, filtering the 
  traffic btw the machines) is preventing the process managers & the MPI 
  procs on the individual machines from contacting each 
  other.

  (Note: 
  Since you do not know what changed in your network, it might help if you try 
  analyzing the network packets sent btw the machines using a packet sniffer 
  like Ethereal.)

  Regards,
  Jayesh

  From: owner-mpich-discuss at mcs.anl.gov 
  [mailto:owner-mpich-discuss at mcs.anl.gov] On Behalf Of Richard 
  Li
Sent: Wednesday, September 05, 2007 8:21 PM
To: 
  mpich-discuss at mcs.anl.gov
Subject: [MPICH] MPI_Bcast hangs in 
  Windows XP

  Hi 
  there,

  I am writing an 
  application in Windows XP/VC8 and am having problem with MPI_Bcast(). I am 
  working in corporate environment and suspect it may have something to do with 
  our security policies, however, I don't know exact which low-level operations 
  failed . 

  Here is the 
  symptom: my application (as well as cpi.exe example) works fine as long as 
  there is only one machine in the machine file, whether its local machine or 
  remote does not matter. It hangs at MPI_Bcast() when I have more than one 
  machine in MPI_COMM_WORLD. I am using mpich2-1.0.5p2-win32-ia32.msi.

  The same 
  application worked perfectly a year ago and there have been many security 
  policy changes since that time(as usual, all policies reduce our freedom). My 
  question is that what's the communication mechanism used in inter-node 
  communication. I tried nothing, auto, sock, ssm as communication channels and 
  had no luck.

  Thanks for your 
  help.

Richard

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