On Mon, Feb 20, 2012 at 06:11:53PM -0500, Rayson Ho wrote: > BTW, since most of the interviewees are opensource project > maintainers, next time can you ask them how much external contribution > they get (%), and who are the main external contributors (students? > HPC labs? Industry?), and how do they handle external contributions > (need copyright assignment?). And how do they handle testing, and > performance regression...
external contributions: I wish I had more quantitative numbers for you. I don't develop on a Lustre system, so we were grateful to the community for contributing and testing an improved Lustre driver for ROMIO. Weikuan Yu started work on a Lustre driver while he worked at Oak Ridge, then Sun/CFS contributed some more improvements. Pascal Deveze from Bull and Martin Pokorny from NRAO helped carry it over the finish line, contributing some important bug fixes and nice little performance improvement tweaks. IBM has been a great industry partner, contributing improvements to all of MPICH2. For BlueGene, IBM contributed a block-aligned collective I/O implementation and an I/O aggregation strategy that works better for the BlueGene topology. They also contributed what we are calling "64 bit MPI_Aint" which works around a problem with MPI file views and platforms with a 32 bit integer. Our best academic partner -- and really at this point we should consider them co-maintainers -- is Northwestern University. I've worked with Wei-Keng for a decade and am always happy to see a question, suggestion, or patch from him in my mailbox. Northwestern provided us some great students over the years as well. Avery Ching and Keenin Coloma did a lot of good work on MPI-IO before the bay area lured them to industry. ROMIO's testing and performance regression framework is honestly a shambles. Part of that is a challenge with the MPI-IO interface itself. For MPI messaging you exercise the API and you have pretty much covered everything. MPI-IO, though, introduces hints. These hints are great for tuning but make the testing "surface area" a lot larger. We are probably going to have a chance to improve things greatly with some recently funded proposals. ==rob -- Rob Latham Mathematics and Computer Science Division Argonne National Lab, IL USA
