[Mpi3-ft] Proposal Update: MPI_ANY_SOURCE, MPI_Abort, MPI_Kill
I updated the run-through stabilization proposal with some of the issues that were brought up during the past two meetings (MPI Forum meeting in Chicago, and teleconf last week). Below is a high-level list of the changes, and below a few topics to discuss: * Added definition of 'fail-stop' and 'transient' process failure * Cleaned up the failure detection text to make it more precise. * Started working on the text clarification for MPI_ANY_SOURCE (see first paragraph of section on 'Ch.3') * Touched up the MPI_Gather example * Added note on MPI_Abort for further discussion * Added start of an interface for MPI_Kill Proposal is here: https://svn.mpi-forum.org/trac/mpi-forum-web/wiki/ft/run_through_stabilizati... MPI_ANY_SOURCE -------------- I made a first attempt at some language for the MPI_ANY_SOURCE specification: https://svn.mpi-forum.org/trac/mpi-forum-web/wiki/ft/run_through_stabilizati... After the teleconf last week it seemed that we probably cannot explicitly say much about the order of delivery of pending messages versus an error class when a process fails on the communicator. What do people think about this? If it helps for comparison, FT-MPI has a couple message modes that they specified (my summaries from [1]): FTMPI_MSG_MODE_RESET: All messages from any process dropped after a failure is detected. FTMPI_MSG_MODE_CONT : Only messages from the failed process are dropped after a failure is detected. MPI_Abort --------- https://svn.mpi-forum.org/trac/mpi-forum-web/wiki/ft/run_through_stabilizati... It was mentioned during the last call that the intention of MPI_Abort is unclear in the case where you specify MPI_COMM_SELF as the argument. I added a couple notes to the wiki about this. It is possible that MPI_Abort should be more carefully defined beyond just this case to, for example, clarify the intention of the communicator argument and its impact of all derived {inter|intra}communicators. MPI_Kill -------- https://svn.mpi-forum.org/trac/mpi-forum-web/wiki/ft/run_through_stabilizati... If MPI_Abort is meant to be a distributed 'exit' option for the MPI application to terminate the whole job, we probably want the ability to remove a specific process from the computation. The MPI_Kill command allows us to specify a specific process to terminate identified by communicator and rank. The process will be excluded from all communicators that it is a part of as if it failed. Do people like this option? Have suggestions on further semantics? Thoughts? -- Josh [1] http://icl.cs.utk.edu/projectsfiles/ftmpi/pubs/isc2004-FT-MPI.pdf ------------------------------------ Joshua Hursey Postdoctoral Research Associate Oak Ridge National Laboratory http://users.nccs.gov/~jjhursey
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Joshua Hursey