Meeting 2016 02 Minutes v2.1 Talk

Notes for the v2.X series

Estimated timeline

• June '15 master branched to 2.0.0
• July '16 2.0.0 is released (yes 1 year and 1 month later!)
• September '16 2.0.1 release
• December '16 2.1.0 release

Must-have Features for 2.0.X

• Thread safety (MPI_THREAD_MULTIPLE) support
  • need to verify which BTLs are thread safe (via testing vs stating) (DONE)
  • need more testing (non-blocking collectives, one-sided, MPI I/O, etc.)
  • need to document what is not thread safe (DONE)
  • performance improvements when using MPI_THREAD_MULTIPLE (i.e., TEST/WAIT improvements) - may wait for a publication before committing
• MPI-3.1 Compliance
  • Ticket #349 (MPI_Aint_add) - 2.0.X candidate (DONE)
  • Ticket #369 (same_disp_info key for MPI_Win_create) - 2.0.X candidate, maybe (DONE)
  • Ticket #273 (non blocking coll I/O, non trivial). This is dependent on moving libnbc core out of libnbc component. (DONE)
  • Ticket #404 (MPI_Aint_diff) - 2.0.X candidate (DONE)
  • Ticket #357 (MPI_Initialized, MPI_Query_thread, MPI_Thread_is_main) always thread safe (probably just verify with a test to see this is true now for OMPI thread models) (DONE)
• MPI-3 Errata Items
  • Ticket #438, MPI_WIN_BASE attribute for shared memory windows
  • Ticket #437, Ticket #434, Ticket #435 - active target sync for shared memory - need to check that OMPI is okay with this one?
  • Ticket #428 - non-profile-able mpi routines
  • Ticket #419 - neighborhood coll can’t handle non-symmetric general graphs, improve error checking
  • Ticket #424 - check fortran9X/F08 interface for MPI_IMPROBE (DONE)
  • Ticket #415, Ticket #345, Ticket #388, Ticket #390 more fortran interface stuff
• Coverity cleanup (IN PROGRESS, down to ~260) (never ending)
• Scalable startup work (smarter add_proc in the OB1 PML), needs more work
  • Sparse groups
  • Additional PMIx features (issue 394)
• ROMIO refresh - need to be using a released ROMIO package (DONE)
• Fix Java bindings garbage collection issues (DONE)
• Hwloc 1.11.3 final (DONE)
• CUDA extension (to add MPIX_CUDA_IS_AWESOME to mpi.h) and MPI_T Cvar for run-time query of whether CUDA is supported in this OMPI
• Add MPI 3 features to Java bindings (DONE)

Must-have Features for the 2.1 Series

• PMIx 2.0 integration
• pending PRs (Nathan's free list work) (DONE)
• Multi-rail performance in OB1? What happened? (WONT FIX)
• TCP latency went up and bandwidth(rendezvous) went way down. What happened? Maybe in 2.x series sometime... (IBM)
• Support for thread-based asynchronous progress for BTLs (anyone working on this now?)
• Improved story on out-of-the-box performance, particularly for collectives. Ideally some kind of auto-tune type of mechanism. (otopo project)

Desirable-to-have Features for 2.1

• Rationalized configuration for Cray XE/XC (DONE)
• platform file for using OFI MTL on Cray XC/KNL
• usNIC stuff
  • conversion to libfabric (DONE)
  • usNIC BTL thread safety PR #1233
• simplified verbs BTL for iWarp? (NOT GOING TO HAPPEN)
• Mellanox stuff
  • HCOLL datatypes
• BTL/OpenIB across different subnets PR #1043
• Open SHMEM 1.3 compliance PR #1041 and PR #1042
• OMPI commands (mpirun, orte_info, etc.): deprecate all single-dash options except for the sacrosanct ones (-np, etc.). Print a stderr warning for all the deprecated options.
  • Note that MPI-3.1 8.8 mpiexec mentions: -soft, -host, -arch, -wdir, -path, -file
• Score-P integration (won't hit 2.0.0, but will get in 2.x)
• libfabric support (Intel MTL, Cisco BTL, others) (DONE in 1.10)
• Memkind support both for MPI_Alloc_mem and Open MPI internal
  • No current owner at Intel for Memkind
• Nathan Hjelmn's BTL 3.0 changes (DONE)
• MPI-4 features (maybe as extensions?)
  • endpoints proposal
  • ULFM (as of June 2015, Ralph/George are coordinating so that ORTE can give ULFM what it needs)
  • MPI T extensions
• Better interop with OpenMP 4 placement - esp. for nested OMP parallelism
• OFI MTL support MPI_THREAD_MULTIPLE - may already be thread safe
• OFI OSC component (probably will not happen)

Features that are already in master that made it in to v2.0

• Switch to using OMPI I/O as default
• Switch to vader as default for shared memory BTL
• PSM2 MTL

Terminating support

• Cray XT legacy items (ESS alps component, etc.) (DONE - although new ess/alps for Cray XE/XC)
• MX BTL (DONE)
• What other BTLs to delete? SCIF?
• Clean up README (DONE)
• Delete coll hierarch component
• coll ML disabled
• Delete VampirTrace interface
• Deprecate mpif77/mpif90: print a stderr warning

Testing

• What do we want to test?
  • More thread safety tests - non blocking collectives, etc.
  • OMPI I/O tests, refresh from HDF group? (DONE)