Hi, No, it just means that *your simulation* does not scale. The question is very vague, hence impossible to answer without more details
However, assuming that you are not running a, say, 5000 atom system over 6 nodes, the most probable reason is that you have 6 Sandy Bridge nodes with 12-16 cores each and 24-32 threads supported. If you just start mdrun with one MPI rank/node it will use 24-32 threads per process which is way too much for parallel runs. Try running with less threads per rank and on less nodes and see if that helps. Cheers, -- Szilárd On Thu, Apr 11, 2013 at 3:23 PM, 陈照云 <chenzhaoyu...@gmail.com> wrote: > Hi! > When I run gromacs-4.6.1 with k20. I meet a question. > I have 6 nodes.And each node has one K20.And I use one process on one > node with one gpu. But the test result shows that the runtime of one node > is less than that of six nodes.Is the scalability of GPU not good? > Thanks! > -- > gmx-users mailing list gmx-users@gromacs.org > http://lists.gromacs.org/mailman/listinfo/gmx-users > * Please search the archive at > http://www.gromacs.org/Support/Mailing_Lists/Search before posting! > * Please don't post (un)subscribe requests to the list. Use the > www interface or send it to gmx-users-requ...@gromacs.org. > * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists -- gmx-users mailing list gmx-users@gromacs.org http://lists.gromacs.org/mailman/listinfo/gmx-users * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! * Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org. * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists