Re: [OMPI users] waiting for message either from MPI communicator or from TCP socket

2017-06-25 Thread Trevour Spencer
Thank you, Brice, you confirmed what I worried about already. So, I will either have a significant overhead from thread context switches or a good amount of my cpu power will go into polling. This is really bad. If there is no interrupt based mechanism such as select(), which can wait for a number

Re: [OMPI users] waiting for message either from MPI communicator or from TCP socket

2017-06-25 Thread Brice Goglin
Usually, when you want to listen to two kinds of event, you use poll/select on Unix (or epoll on Linux). This strategy doesn't work for MPI events because MPI doesn't provide a Unix file descriptor to pass to poll/select/epoll. One work-around is to have one thread listen to MPI events. When it

Re: [OMPI users] waiting for message either from MPI communicator or from TCP socket

2017-06-25 Thread r...@open-mpi.org
I suspect nobody is answering because the question makes no sense to us. You are implying that the TCP socket is outside of MPI since it isn’t tied to a communicator. If you want to setup a non-MPI communication path between two procs and monitor it separate from the MPI library, you can

Re: [OMPI users] waiting for message either from MPI communicator or from TCP socket

2017-06-25 Thread Trevour Spencer
Dear all, I have not yet found a solution for waiting for an event (incoming message) to occur either on a TCP socket or on a MPI communicator. I wish I could receive some comments from you MPI experts. If my question was unclear, I found the same problem described on the MPICH list two years ago: