My only concern is how will this interact with PLPA. Say two Open MPI jobs each use "half" the cores (slots) on a particular node... how would they be able to bind themselves to a disjoint set of cores? I'm not asking you to solve this Ralph, I'm just pointing it out so we can maybe warn users that if both jobs sharing a node try to use processor affinity, we don't make that magically work well, and that we would expect it to do quite poorly.
I could see disabling paffinity and/or warning if it was enabled for one of these "fractional" nodes. On Mon, Jul 28, 2008 at 11:43 AM, Ralph Castain <r...@lanl.gov> wrote: > Per an earlier telecon, I have modified the hostfile behavior slightly to > allow hostfiles to subdivide allocations. > > Briefly: given an allocation, we allow users to specify --hostfile on a > per-app_context basis. In this mode, the hostfile info is used to filter the > nodes that will be used for that app_context. However, the prior > implementation only filtered the nodes themselves - i.e., it was a binary > filter that allowed you to include or exclude an entire node. > > The change now allows you to include a specified #slots for a given node as > opposed to -all- slots from that node. You are limited to the #slots > included in the original allocation. I just realized that I hadn't output a > warning if you attempt to violate this condition - will do so shortly. > Rather than just abort if this happens, I set the allocation to that of the > original - please let me know if you would prefer it to abort. > > If you have interest in this behavior, please check it out and let me know > if this meets needs. > > Ralph > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel > -- Tim Mattox, Ph.D. - http://homepage.mac.com/tmattox/ tmat...@gmail.com || timat...@open-mpi.org I'm a bright... http://www.the-brights.net/
