Made a couple vars static if they didn't look like they were used
more than one place, and added prefixes to a few.
Signed-off-by: Mark Allen <markalle@us.ibm.com>
(cherry picked from commit 34b42b1b0996049aea60c72f2a1505c5d1e55b8c)
Use the PVAR ctx to save the SPC index, so that no lookup nor
restriction on the SPC vars position is imposed.
Make sure the PVAR are always registered.
Signed-off-by: George Bosilca <bosilca@icl.utk.edu>
This code is the implementation of Software-base Performance Counters as described in the paper 'Using Software-Base Performance Counters to Expose Low-Level Open MPI Performance Information' in EuroMPI/USA '17 (http://icl.cs.utk.edu/news_pub/submissions/software-performance-counters.pdf). More practical usage information can be found here: https://github.com/davideberius/ompi/wiki/How-to-Use-Software-Based-Performance-Counters-(SPCs)-in-Open-MPI.
All software events functions are put in macros that become no-ops when SOFTWARE_EVENTS_ENABLE is not defined. The internal timer units have been changed to cycles to avoid division operations which was a large source of overhead as discussed in the paper. Added a --with-spc configure option to enable SPCs in the Open MPI build. This defines SOFTWARE_EVENTS_ENABLE. Added an MCA parameter, mpi_spc_enable, for turning on specific counters. Added an MCA parameter, mpi_spc_dump_enabled, for turning on and off dumping SPC counters in MPI_Finalize. Added an SPC test and example.
Signed-off-by: David Eberius <deberius@vols.utk.edu>
