Open MPI User's Mailing List Archives

Subject: Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes
From: Eugene Loh (Eugene.Loh_at_[hidden])
Date: 2009-12-04 14:10:14

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On Fri, Dec 4, 2009 at 10:29, Eugene Loh <Eugene.Loh@sun.com> wrote:

I think you might observe a world of difference if the master issued some non-blocking call and then intermixed MPI_Test calls with sleep calls.  You should see *much* more subservient behavior.  As I remember, putting such passivity into OMPI is on somebody's to-do list, but just not very high.

could you give me more details?

I can't figure out how to do this. I could see that one way to implement what you are describing is:

in slave.c:
MPI_Send() to rank 0

in master.c
MPI_IRecv() from the spawned processes
while (1) {  MPI_Test(); }

I can't figure out how to find the ranks that MPI_Comm_spawn() used. What's the source argument in MPI_IRecv() supposed to be?

• Next message: Jeremiah Willcock: "[OMPI users] Typo in mpirun man page"
• Previous message: Jeff Squyres: "Re: [OMPI users] Mimicking timeout for MPI_Wait"
• In reply to: Nicolas Bock: "Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes"
• Next in thread: Nicolas Bock: "Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes"
• Reply: Nicolas Bock: "Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes"