Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

On Fri, Dec 4, 2009 at 12:10, Eugene Loh wrote: > Nicolas Bock wrote: > > On Fri, Dec 4, 2009 at 10:29, Eugene Loh 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 *

Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

Nicolas Bock wrote: On Fri, Dec 4, 2009 at 10:29, Eugene Loh 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. 

Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

On Fri, Dec 4, 2009 at 10:29, Eugene Loh wrote: > Nicolas Bock wrote: > > On Fri, Dec 4, 2009 at 10:10, Eugene Loh wrote: > >> Yield helped, but not as effectively as one might have imagined. >> > > Yes, that's the impression I get as well, the master process might be > yielding, but it doesn't

Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

Nicolas Bock wrote: On Fri, Dec 4, 2009 at 10:10, Eugene Loh wrote: Yield helped, but not as effectively as one might have imagined. Yes, that's the impression I get as well, the master process might be yielding, but it doesn't appear to be a lot. Maybe

Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

On Fri, Dec 4, 2009 at 10:10, Eugene Loh wrote: > Nicolas Bock wrote: > > On Fri, Dec 4, 2009 at 08:21, Ralph Castain wrote: > >> You used it correctly. Remember, all that cpu number is telling you is the >> percentage of use by that process. So bottom line is: we are releasing it as >> much as

Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

Nicolas Bock wrote: On Fri, Dec 4, 2009 at 08:21, Ralph Castain wrote: You used it correctly. Remember, all that cpu number is telling you is the percentage of use by that process. So bottom line is: we are releasing it as much as we possibly can, but no other proc

Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

On Fri, Dec 4, 2009 at 08:21, Ralph Castain wrote: > You used it correctly. Remember, all that cpu number is telling you is the > percentage of use by that process. So bottom line is: we are releasing it as > much as we possibly can, but no other process wants to use the cpu, so we go > ahead and

Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

You used it correctly. Remember, all that cpu number is telling you is the percentage of use by that process. So bottom line is: we are releasing it as much as we possibly can, but no other process wants to use the cpu, so we go ahead and use it. If any other process wanted it, then the percent

Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

On Fri, Dec 4, 2009 at 08:03, Ralph Castain wrote: > > > It is polling at the barrier. This is done aggressively by default for > performance. You can tell it to be less aggressive if you want via the > yield_when_idle mca param. > > How do I use this parameter correctly? I tried /usr/local/open

Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

On Dec 4, 2009, at 7:46 AM, Nicolas Bock wrote: > Hello list, > > when I run the attached example, which spawns a "slave" process with > MPI_Comm_spawn(), I see the following: > > nbock19911 0.0 0.0 53980 2288 pts/0S+ 07:42 0:00 > /usr/local/openmpi-1.3.4-gcc-4.4.2/bin/mpirun

[OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes

Hello list, when I run the attached example, which spawns a "slave" process with MPI_Comm_spawn(), I see the following: nbock19911 0.0 0.0 53980 2288 pts/0S+ 07:42 0:00 /usr/local/openmpi-1.3.4-gcc-4.4.2/bin/mpirun -np 3 ./master nbock19912 92.1 0.0 158964 3868 pts/0R+