There is no problem with using numerical host names - we don’t care so long as your system can resolve them. The difference you are seeing relates to a change in behavior created during the 1.7 series. If you don’t specify the #slots on a host, then we automatically set it to the number of detected cores on that node. Specifying the #slots overrides that detection logic.
> On Oct 7, 2015, at 2:55 PM, John Marshall <john.marsh...@ssc-spc.gc.ca> wrote: > > Hi, > > I've been running with 1.6.5 for some time and am now trying out 1.8.8 (I'll > get to 1.10 soon). > I have found a difference in behavior and I'm wondering what is happening. > > For special reasons, I have a host file which uses index values as logical > names: > 0 > 1 > 2 > 3 > These are properly understood by the launcher. With 1.6.5, when I do: > mpirun hostname > I get 4 lines of output. > > However, when I do the same with 1.8.8 on a 16 cpu machine, I get 64 lines of > output. > > If I change my hostfile to: > 0 slots=1 > 1 slots=1 > 2 slots=1 > 3 slots=1 > I get only 4 lines with 1.8.8. > > Can you explain why I see the behavior I do, specifically, getting the 64 > lines of output? Is the > interpretation of the hostfile different between 1.6.5 and 1.8.8? Are logical > names without the > "slots=1" (now?) treated differently than hostnames? > > Thanks, > John > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2015/10/27838.php
