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Subject: Re: [OMPI users] mpi job is blocked
From: Richard (codemonkee_at_[hidden])
Date: 2012-09-25 06:27:15


I used "chkconfig --list iptables ", none of computer is set as "on".

At 2012-09-25 17:54:53,"Jeff Squyres" <jsquyres_at_[hidden]> wrote:

>Hav you disabled firewalls on your nodes (e.g., iptables)?
>
>On Sep 25, 2012, at 11:08 AM, Richard wrote:
>
>> sometimes the following message jumped out when I run the ring program, but not always.
>> I do not know this ip address 192.168.122.1, it is not in my list of hosts.
>>
>>
>> [[53402,1],6][btl_tcp_endpoint.c:638:mca_btl_tcp_endpoint_complete_connect] connect() to 192.168.122.1 failed: Connection refused (111
>>
>>
>>
>>
>>
>> At 2012-09-25 16:53:50,Richard <codemonkee_at_[hidden]> wrote:
>>
>> if I tried the ring program, the first round of pass is fine, but the second round is blocked at some node.
>> here is the message printed out
>>
>> Process 0 sending 10 to 1, tag 201 (3 processes! in ring)
>> Process 0 sent to 1
>> rank 1, message 10,start===========
>> rank 1, message 10,end-------------
>> rank 2, message 10,start===========
>> Process 0 decremented value: 9
>> rank 0, message 9,start===========
>> rank 0, message 9,end-------------
>> rank 2, message 10,end-------------
>> rank 1, message 9,start===========
>>
>> I have added some printf statements in the ring_c.c as follows:
>> 60 printf("rank %d, message %d,start===========\n", rank, message);
>> 61 MPI_Send(&message, 1, MPI_INT, ! next, tag, MPI_COMM_WORLD);
>> 62 printf("rank %d, message %d,end-------------\n", rank, message);
>>
>>
>>
>> At 2012-09-25 16:30:01,Richard <codemonkee_at_[hidden]> wrote:
>> Hi Jody,
>> thanks for your suggestion and you are right. if I use the ring example, the same happened.
>> I have put a printf statement, it seems that all the three processed have reached the line
>> calling "PMPI_Allreduce", any further suggestion?
>>
>> Thanks.
>> Richard
>>
>>
>>
>> Message: 12
>> Date: Tue, 25 Sep 2012 09:43:09 +0200
>> From: jody <
>> jody.xha_at_[hidden]
>> >
>> Subject: Re: [OMPI users] mpi job is blocked
>> To: Open MPI Users <
>> users_at_[hidden]
>> >
>> Message-ID:
>> <
>> CAKbzMGfL0tXDYU82HksoHrwh34CbpwbKmrKwC5DcDBT7A7wTxw_at_[hidden]
>> >
>> Content-Type: text/plain; charset=ISO-8859-1
>>
>> Hi Richard
>>
>> When a collective call hangs, this usually means that one (or more)
>> processes did not reach this command.
>> Are you sure that all processes reach the allreduce statement?
>>
>> If something like this happens to me, i insert print statements just
>> before the MPI-call so i can see which processes made
>> it to this point and which ones did not.
>>
>> Hope this helps a bit
>> Jody
>>
>> On Tue, Sep 25, 2012 at 8:20 AM, Richard <
>> codemonkee_at_[hidden]
>> > wrote:
>> > I have 3 computers with the same Linux system. I have setup the mpi cluster
>> > based on ssh connection.
>> > I have tested a very simple mpi program, it works on the cluster.
>> >
>> > To make my story clear, I name the three computer as A, B and C.
>> >
>> > 1) If I run the job with 2 processes on A and B, it works.
>> > 2) if I run the job with 3 processes on A, B and C, it is blocked.
>> > 3) if I run the job with 2 processes on A and C, it works.
>> > 4) If I run the job with all the 3 processes on A, it works.
>> >
>> > Using gdb I found the line at which it is blocked, it is here
>> >
>> > #7 0x00002ad8a283043e in PMPI_Allreduce (sendbuf=0x7fff09c7c578,
>> > recvbuf=0x7fff09c7c570, count=1, datatype=0x627180, op=0x627780,
>> > comm=0x627380)
>> > at pallreduce.c:105
>> > 105 err = comm->c_coll.coll_allreduce(sendbuf, recvbuf, count,
>> >
>> > It seems that there is a communication problem between some computers. But
>> > the above series of test cannot tell me what
>> > exactly it is. Can anyone help me? thanks.
>> >
>> > Richard
>> >
>> >
>> >
>> >
>> > _______________________________________________
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>> >
>> users_at_[hidden]
>>
>> > http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>>
>>
>>
>>
>>
>>
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>
>
>--
>Jeff Squyres
>jsquyres_at_[hidden]
>For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
>
>
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