Open MPI logo

Open MPI User's Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Open MPI User's mailing list

Subject: Re: [OMPI users] CPU burning in Wait state
From: Vincent Rotival (vincent.rotival_at_[hidden])
Date: 2008-09-03 13:11:00


Eugene,

No what I'd like is that when doing something like

call mpi_bcast(data, 1, MPI_INTEGER, 0, .....)

the program continues AFTER the Bcast is completed (so no control
returned to user), but while threads with rank > 0 are waiting in Bcast
they are not taking CPU resources

I hope it is more clear, I apologize for not being clear in the first place

Vincent

Eugene Loh wrote:
>
> Vincent Rotival wrote:
>
>> The solution I retained was for the main thread to isend data
>> separately to each other threads that are using Irecv + loop on
>> mpi_test to test the finish of the Irecv. It mught be dirty but
>> works much better than using Bcast
>
> Thanks for the clarification.
>
> But this strikes me more as a question about the MPI standard than
> about the Open MPI implementation. That is, what you really want is
> for the MPI API to support a non-blocking form of collectives. You
> want control to return to the user program before the
> barrier/bcast/etc. operation has completed. That's an API change.
> _______________________________________________
> users mailing list
> users_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/users
>
>