[Mpi3-hybridpm] [MPI Forum] #211: MPI3 Hybrid Programming: multiple endpoints per collective, option 4

[MPI Forum]

#211: MPI3 Hybrid Programming: multiple endpoints per collective, option 4
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                    Reporter:  dougmill@…                 |                       Owner:  dougmill@…             
                        Type:  Enhancements to standard   |                      Status:  new                    
                    Priority:  Not ready / author rework  |                   Milestone:  2010/01/19 Atlanta, USA
                     Version:  MPI 3.0                    |                    Keywords:                         
              Implementation:  Unnecessary                |           Author_bill_gropp:  0                      
          Author_rich_graham:  0                          |           Author_adam_moody:  0                      
      Author_torsten_hoefler:  0                          |        Author_dick_treumann:  0                      
Author_jesper_larsson_traeff:  0                          |       Author_george_bosilca:  0                      
           Author_david_solt:  0                          |   Author_bronis_de_supinski:  0                      
        Author_rajeev_thakur:  0                          |         Author_jeff_squyres:  0                      
    Author_alexander_supalov:  0                          |    Author_rolf_rabenseifner:  0                      
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Comment(by dougmill@…):

 Some possible example code:
 {{{
 #pragma omp parallel num_threads(max)
 {
     ...
     /* computation... */
     ...
     x = omp_get_thread_num();
     #pragma omp master
     {
         MPI_Endpoint_attach(endpoints[x]);
         ...
         /* communications... */
         ...
         MPI_Endpoint_detach_helper();
         MPI_Endpoint_detach();
     }
     #pragma omp !master /* how is this done? */
     {
         MPI_Endpoint_attach_helper(endpoints[x]);
         /* these threads do no communication! */
     }
     ...
     /* more computation, communication, etc */
     ...
 }
 }}}

 In this example, the non-master threads/agents do not do any
 communications explicitly. If they did, there would need to be some sort
 of coordination with the master thread, and they would perform (start)
 their communications and then make the attach helper call. It is unclear
 if there would be deadlock scenarios with that.

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Ticket URL: <https://svn.mpi-forum.org/trac/mpi-forum-web/ticket/211#comment:2>
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