Hi Eugen, thanks for your answer ... I am beginning to understand - even though I am not happy with it :)
Greetings Jens Eugene Loh schrieb: > Jens wrote: > >> Hi Terry, >> >> I would like to run a paraview-server all time on our cluster (even >> though it is not in use 24h) - but this would simply result in some kind >> of "heating-thread". >> >> Even though it has (in theory) no impact on the node performace (which >> is part of a grid-engine), it would simply result in some kind of >> "heating-thread" which is not a nice idea. >> >> > Further (and you can test this), it doesn't yield 100% effectively. > E.g., even if you had other processes ready and eager to consume the > CPU, it seems (based on my tests) that a waiting/yielding OMPI process > won't give up the CPU very well. E.g., maybe only 50%. > > An MPI implementation could be more cautious. E.g., it could put a > process to sleep and poll only occasionally for in-coming messages or > have some other way of waking up when needed. > > The trade-offs are: > > *) the more you give up the CPU, the longer it takes to wake up > *) the more control over this trade off you give to the user, the more > the user needs to understand the tradeoffs > *) the more control you want to allow, the more complex the MPI > implementation > > Regarding the last one, I think OMPI only allows aggressive or else > yield. No sleep. > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
