Re: [OMPI users] Open MPI and MultiRail InfiniBand

out we > can patch the release branch. Actually you do...:-) Please let me know if you ever intend to use that system. I am now letting someone else use it, but it can be shared. -- Jean-Christophe Hugly PANTA

Re: [O-MPI users] direct openib btl and latency

the difference visible at 32 is pretty small. So, it is application dependent, no question about it, but small-msg rdma is beneficial below a given (application-dependent) cluster size. -- Jean-Christophe Hugly PANTA

Re: [O-MPI users] direct openib btl and latency

number of anecdotal reports I got. It may well be that in some situations, small-msg rdma is better only for 2 nodes, but that's note such a likely scenario; reality is sometimes linear (at least at our scale :-) ) after all. The scale threshold could be tunable, couldnt it ? -- Jean-Christophe Hugly PANTA

Re: [O-MPI users] direct openib btl and latency

hine in micro-benchmarks is important, even if it means using an ad-hoc tuning. There is some justification for it after all. There are small clusters out there (many more than big ones, in fact) so taking maximum advantage of a small scale is relevant. When do you plan on having the small-msg rdma option available ? J-C -- Jean-Christophe Hugly PANTA

Re: [O-MPI users] direct openib btl and latency

of 0.5 us). Thanks, guys. I'll stop worrying about that then ! -- Jean-Christophe Hugly PANTA

Re: [O-MPI users] direct openib btl and latency

e opposite (which was my initial expectation, actually). May be I just misunderstood the whole set of tunables. My understanding was that messages under the eager limit would never be rdma'd by definition, and that the others would or would not be, depending on the min_rdma_size. -- Jean-Christophe Hugly PANTA

[O-MPI users] direct openib btl and latency

x27;l settle for 1.5 :-) ) Any advice ? -- Jean-Christophe Hugly PANTA

Re: [O-MPI users] does btl_openib work with multiple ports ?

tant to us. Not only are we very much interrested by ompi's multi-rail feature, but also we use IB for other things than MPI and spread the load over the two ports. Is there a special way of configuring ompi for it to work properly with multiple ports ? -- Jean-Christophe Hugly PANTA

Re: [O-MPI users] does btl_openib work ?

On Thu, 2006-02-02 at 15:19 -0700, Galen M. Shipman wrote: > Is it possible for you to get a stack trace where this is hanging? > > You might try: > > > mpirun -prefix /opt/ompi -wdir `pwd` -machinefile /root/machines -np > 2 -d xterm -e gdb PMB-MPI1 > > I did that, and when it was hanging

Re: [O-MPI users] does btl_openib work ?

On Thu, 2006-02-02 at 15:19 -0700, Galen M. Shipman wrote: > By using slots=4 you are telling Open MPI to put the first 4 > processes on the "bench1" host. > Open MPI will therefore use shared memory to communicate between the > processes not Infiniband. Well, actually not, unless I'm mistaken

Re: [O-MPI users] does btl_openib work ?

d > note that you said you configured both with and without threads but > try the configure on a fresh source, not on one that had previously > been configured with thread support. I rebuilt everything from fresh src (took the oppotunity to refresh). Same behaviour... Am I the only on

[O-MPI users] does btl_openib work ?

ing ? -- Jean-Christophe Hugly PANTA

[O-MPI users] does btl_openib work ?

max-slots=4 Am I doing something obviously wrong ? Thanks for any help ! -- Jean-Christophe Hugly PANTA