I'm afraid our suspend/resume support only allows the signal to be applied to *all* procs, not selectively to some. For that matter, I'm unaware of any MPI-level API for hitting a proc with a signal - so I'm not sure how you would programmatically have rank0 suspend some other ranks.
On Apr 11, 2014, at 12:16 PM, Frank Wein <mcsm...@mcsmurf.de> wrote: > Hi, > I've got a question on suspending/resuming an process started with > "mpirun", I've already found the FAQ entry on this > http://www.open-mpi.de/faq/?category=running#suspend-resume but I've > still got a question on this. Basically for now let's assume I'm running > all MPI processes on one host only with one multi-core CPU (so I could > directly send SIGSTOP to other processes if I want to). What I wonder > about is the following: I want to start multiple (let's say four) > instances of my program with "mpirun -np 4 ./mybinary" and at some point > during the program execution I want to suspend two of those four > processes, those two processes are waiting at an MPI_Barrier() at this > point. The goal of that is to suspend execution so that those processes > don't use the CPU at all while they are suspended (that's not the case > with MPI_Barrier as far as I understand this). So now my question > basically is: Will it work when I send SIGSTOP signal from my MPI rank 0 > process to these two processes while they are waiting at an MPI_Barrier > and then those two processes won't use the CPU anymore? Later I want to > resume the processes with SIGCONT when the other two processes also > arrived at this MPI_Barrier. Performance of the barrier does not matter > here, what matters for me is that those suspended processes don't cause > any CPU usage. I never used SIGSTOP signal so far, so I'm not sure if > this will work. And before I start coding the logic for this into my > program, I thought I'll ask here first if this will work at all :). > > Frank > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
