Open MPI logo

Open MPI Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Development mailing list

Subject: Re: [OMPI devel] MPI_Comm_connect/Accept
From: Ralph H Castain (rhc_at_[hidden])
Date: 2008-04-04 14:26:26


Yeah, you didn't specify the file correctly...plus I found a bug in the code
when I looked (out-of-date a little in orterun).

I am updating orterun (commit soon) and will include a better help message
about the proper format of the orterun cmd-line option. The syntax is:

-ompi-server uri

or -ompi-server file:filename-where-uri-exists

Problem here is that you gave it a uri of "test", which means nothing. ;-)

Should have it up-and-going soon.
Ralph

On 4/4/08 12:02 PM, "Aurélien Bouteiller" <bouteill_at_[hidden]> wrote:

> Ralph,
>
> I've not been very successful at using ompi-server. I tried this :
>
> xterm1$ ompi-server --debug-devel -d --report-uri test
> [grosse-pomme.local:01097] proc_info: hnp_uri NULL
> daemon uri NULL
> [grosse-pomme.local:01097] [[34900,0],0] ompi-server: up and running!
>
>
> xterm2$ mpirun -ompi-server test -np 1 mpi_accept_test
> Port name:
> 2285895681.0;tcp://192.168.0.101:50065;tcp://192.168.0.150:50065:300
>
> xterm3$ mpirun -ompi-server test -np 1 simple_connect
> --------------------------------------------------------------------------
> Process rank 0 attempted to lookup from a global ompi_server that
> could not be contacted. This is typically caused by either not
> specifying the contact info for the server, or by the server not
> currently executing. If you did specify the contact info for a
> server, please check to see that the server is running and start
> it again (or have your sys admin start it) if it isn't.
>
> --------------------------------------------------------------------------
> [grosse-pomme.local:01122] *** An error occurred in MPI_Lookup_name
> [grosse-pomme.local:01122] *** on communicator MPI_COMM_WORLD
> [grosse-pomme.local:01122] *** MPI_ERR_NAME: invalid name argument
> [grosse-pomme.local:01122] *** MPI_ERRORS_ARE_FATAL (goodbye)
> --------------------------------------------------------------------------
>
>
>
> The server code Open_port, and then PublishName. Looks like the
> LookupName function cannot reach the ompi-server. The ompi-server in
> debug mode does not show any output when a new event occurs (like when
> the server is launched). Is there something wrong in the way I use it ?
>
> Aurelien
>
> Le 3 avr. 08 à 17:21, Ralph Castain a écrit :
>> Take a gander at ompi/tools/ompi-server - I believe I put a man page
>> in
>> there. You might just try "man ompi-server" and see if it shows up.
>>
>> Holler if you have a question - not sure I documented it very
>> thoroughly at
>> the time.
>>
>>
>> On 4/3/08 3:10 PM, "Aurélien Bouteiller" <bouteill_at_[hidden]>
>> wrote:
>>
>>> Ralph,
>>>
>>>
>>> I am using trunk. Is there a documentation for ompi-server ? Sounds
>>> exactly like what I need to fix point 1.
>>>
>>> Aurelien
>>>
>>> Le 3 avr. 08 à 17:06, Ralph Castain a écrit :
>>>> I guess I'll have to ask the basic question: what version are you
>>>> using?
>>>>
>>>> If you are talking about the trunk, there no longer is a "universe"
>>>> concept
>>>> anywhere in the code. Two mpiruns can connect/accept to each other
>>>> as long
>>>> as they can make contact. To facilitate that, we created an "ompi-
>>>> server"
>>>> tool that is supposed to be run by the sys-admin (or a user, doesn't
>>>> matter
>>>> which) on the head node - there are various ways to tell mpirun
>>>> how to
>>>> contact the server, or it can self-discover it.
>>>>
>>>> I have tested publish/lookup pretty thoroughly and it seems to
>>>> work. I
>>>> haven't spent much time testing connect/accept except via
>>>> comm_spawn, which
>>>> seems to be working. Since that uses the same mechanism, I would
>>>> have
>>>> expected connect/accept to work as well.
>>>>
>>>> If you are talking about 1.2.x, then the story is totally different.
>>>>
>>>> Ralph
>>>>
>>>>
>>>>
>>>> On 4/3/08 2:29 PM, "Aurélien Bouteiller" <bouteill_at_[hidden]>
>>>> wrote:
>>>>
>>>>> Hi everyone,
>>>>>
>>>>> I'm trying to figure out how complete is the implementation of
>>>>> Comm_connect/Accept. I found two problematic cases.
>>>>>
>>>>> 1) Two different programs are started in two different mpirun. One
>>>>> makes accept, the second one use connect. I would not expect
>>>>> MPI_Publish_name/Lookup_name to work because they do not share the
>>>>> HNP. Still I would expect to be able to connect by copying (with
>>>>> printf-scanf) the port_name string generated by Open_port;
>>>>> especially
>>>>> considering that in Open MPI, the port_name is a string containing
>>>>> the
>>>>> tcp address and port of the rank 0 in the server communicator.
>>>>> However, doing so results in "no route to host" and the connecting
>>>>> application aborts. Is the problem related to an explicit check of
>>>>> the
>>>>> universes on the accept HNP ? Do I expect too much from the MPI
>>>>> standard ? Is it because my two applications does not share the
>>>>> same
>>>>> universe ? Should we (re) add the ability to use the same universe
>>>>> for
>>>>> several mpirun ?
>>>>>
>>>>> 2) Second issue is when the program setup a port, and then accept
>>>>> multiple clients on this port. Everything works fine for the first
>>>>> client, and then accept stalls forever when waiting for the second
>>>>> one. My understanding of the standard is that it should work: 5.4.2
>>>>> states "it must call MPI_Open_port to establish a port [...] it
>>>>> must
>>>>> call MPI_Comm_accept to accept connections from clients". I
>>>>> understand
>>>>> that for one MPI_Open_port I should be able to manage several MPI
>>>>> clients. Am I understanding correctly the standard here and
>>>>> should we
>>>>> fix this ?
>>>>>
>>>>> Here is a copy of the non-working code for reference.
>>>>>
>>>>> /*
>>>>> * Copyright (c) 2004-2007 The Trustees of the University of
>>>>> Tennessee.
>>>>> * All rights reserved.
>>>>> * $COPYRIGHT$
>>>>> *
>>>>> * Additional copyrights may follow
>>>>> *
>>>>> * $HEADER$
>>>>> */
>>>>> #include <stdlib.h>
>>>>> #include <stdio.h>
>>>>> #include <mpi.h>
>>>>>
>>>>> int main(int argc, char *argv[])
>>>>> {
>>>>> char port[MPI_MAX_PORT_NAME];
>>>>> int rank;
>>>>> int np;
>>>>>
>>>>>
>>>>> MPI_Init(&argc, &argv);
>>>>> MPI_Comm_rank(MPI_COMM_WORLD, &rank);
>>>>> MPI_Comm_size(MPI_COMM_WORLD, &np);
>>>>>
>>>>> if(rank)
>>>>> {
>>>>> MPI_Comm comm;
>>>>> /* client */
>>>>> MPI_Recv(port, MPI_MAX_PORT_NAME, MPI_CHAR, 0, 0,
>>>>> MPI_COMM_WORLD, MPI_STATUS_IGNORE);
>>>>> printf("Read port: %s\n", port);
>>>>> MPI_Comm_connect(port, MPI_INFO_NULL, 0, MPI_COMM_SELF,
>>>>> &comm);
>>>>>
>>>>> MPI_Send(&rank, 1, MPI_INT, 0, 1, comm);
>>>>> MPI_Comm_disconnect(&comm);
>>>>> }
>>>>> else
>>>>> {
>>>>> int nc = np - 1;
>>>>> MPI_Comm *comm_nodes = (MPI_Comm *) calloc(nc,
>>>>> sizeof(MPI_Comm));
>>>>> MPI_Request *reqs = (MPI_Request *) calloc(nc,
>>>>> sizeof(MPI_Request));
>>>>> int *event = (int *) calloc(nc, sizeof(int));
>>>>> int i;
>>>>>
>>>>> MPI_Open_port(MPI_INFO_NULL, port);
>>>>> /* MPI_Publish_name("test_service_el", MPI_INFO_NULL,
>>>>> port);*/
>>>>> printf("Port name: %s\n", port);
>>>>> for(i = 1; i < np; i++)
>>>>> MPI_Send(port, MPI_MAX_PORT_NAME, MPI_CHAR, i, 0,
>>>>> MPI_COMM_WORLD);
>>>>>
>>>>> for(i = 0; i < nc; i++)
>>>>> {
>>>>> MPI_Comm_accept(port, MPI_INFO_NULL, 0, MPI_COMM_SELF,
>>>>> &comm_nodes[i]);
>>>>> printf("Accept %d\n", i);
>>>>> MPI_Irecv(&event[i], 1, MPI_INT, 0, 1, comm_nodes[i],
>>>>> &reqs[i]);
>>>>> printf("IRecv %d\n", i);
>>>>> }
>>>>> MPI_Close_port(port);
>>>>> MPI_Waitall(nc, reqs, MPI_STATUSES_IGNORE);
>>>>> for(i = 0; i < nc; i++)
>>>>> {
>>>>> printf("event[%d] = %d\n", i, event[i]);
>>>>> MPI_Comm_disconnect(&comm_nodes[i]);
>>>>> printf("Disconnect %d\n", i);
>>>>> }
>>>>> }
>>>>>
>>>>> MPI_Finalize();
>>>>> return EXIT_SUCCESS;
>>>>> }
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> * Dr. Aurélien Bouteiller
>>>>> * Sr. Research Associate at Innovative Computing Laboratory
>>>>> * University of Tennessee
>>>>> * 1122 Volunteer Boulevard, suite 350
>>>>> * Knoxville, TN 37996
>>>>> * 865 974 6321
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> devel mailing list
>>>>> devel_at_[hidden]
>>>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> devel mailing list
>>>> devel_at_[hidden]
>>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>>
>>>
>>> _______________________________________________
>>> devel mailing list
>>> devel_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>
>>
>>
>> _______________________________________________
>> devel mailing list
>> devel_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>
>
> _______________________________________________
> devel mailing list
> devel_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/devel