HHAT Usage Meeting Minutes

This wiki page is used to keep minutes from phone and face to face meetings on the topic of usage models, user stories, and applications for heterogeneous hierarchical asynchronous tasking. Most recent meetings are listed on top.

Kickoff, Dec. 20, 2016

Agenda

• Welcome: Wilf Pinfold
• Overview, purpose
• Approach
• Wiki explanation
• Next steps
• Feedback, expression of interest

Participants (33) included

BillF, CarterE, DavidR, Erik, JimP, KamilH & RomanW, PatrickA, PietroC, SenT, ShekharB, CJ, WilfP, StephenJ, XinchenG, TimM, RomainC, OscarH, AlexandrN, VinodG, KathK, Ashwin Aji, JoshF, GalenS, ManjuG, PallS, MariaG, ...
See calendar entry, if you signed up

Discussion

• Glossary suggested by Tim, try not to invent new definitions
• Report suggested by Oscar - summary of usage cases could be useful for DoE
• How do we keep from getting fragmented? (Tim) Try to bringing community together by focusing on common requirements (Wilf)
• Start with usage models, requirements, provisioning constraints, rather than comparing and contrasting specific implementations
• We have data and experience to share
• Looking to have a phone meeting 3rd Tue each month at 9am PST; some here had standing conflicts; Wilf to try a Doodle poll
• Time scale, involvement, outputs?
• Are we sold on async tasking? Driven more by efficiency on HW? (Shekhar) Yes (Oscar) Who needs it for what? We need compelling examples of where mainline DoE apps need it. (Dave Richards) Clever use of MPI goes a long way (Tim)
• MPI: resilience not well addressed (Wilf) Comparison with MPI is inappropriate, tasking can be done on top of MPI, e.g. two-hot, accelerated MD. It's about the benefit of a computational model, which helps some and not others. (Galen) Tim agrees that MPI is low-level runtime.
• Interesting to identify a set of apps that embody tasking, and understand why they chose that model (Galen) Sounds like a potential value proposition (Shekhar).
• Characteristics: granularity of tasks - the finer the granularity the less portable the solution, explicit vs. implicit control (DaveR) If task relationships can be described, it can become more portable (Stephen) How will decomposition happen - expert, compiler, runtime? (DaveR)
• How do we make this applicable to large, portable code bases, enabling productivity? Where does the tasking model emerge? (DaveR)
• What does it mean to have an async environment, what are the critical features? (Josh)
• The way to resolving differences at various levels may lie in hierarchy (Kath) Strongly agree with hierarchy (Tim)
• Strongly agree with a bottom up approach, with a hierarchical perspective (Tim)