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.

Community meeting, Jan 17, 2017

Agenda

• Welcome: Wilf Pinfold
• Overview, purpose
• Solicit apps that need hierarchical tasking
• Solicit usage models
  • Fully dynamic to semi-static - Pall
• Solicit user stories (requirements)
  • Map tasks to multiple GPUs - Dmitry
  • Granularity - Pall
  • Finite memory - Carter
  • Distributed data structures in finite memory - Toby
  • For latency sensitivity apps, anything overheads need to be offset by significant gains - Pall
  • Hierarchical topology - Toby
  • Building libs for finite physical memory; libs cooperating with caller, e.g. via callbacks - John Stone
  • Aggregated task groups, recursive task model that enables decomposition - Dmitry, Ashwin Aji
  • Data affinity-driven binding and scheduling and data decomposition - Pall
  • Move work to data vs. other way around - John
  • PGAS support, data affinity and decomposition - Toby
• Housekeeping - Wilf

Participants included: Wilfred Pinfold - creator, John Stone, umit@gatech.edu, Wael Elwasif, xg@purdue.edu Xinchen Guo, belak1@llnl.gov, Ruymán Reyes, pa13269@bristol.ac.uk Patrick Atkinson, Max Grossman, gordon@codeplay.com, bala.seshasayee@intel.com, mbianco@cscs.ch, ashwin.aji@amd.com, khalbiniak@icis.pcz.pl, fabien.delalondre@epfl.ch, richards12@llnl.gov, pszilard@kth.se, Michael Wong, Shekhar Borkar, David Bernholdt, rabuch2@illinois.edu, bill@feiereisen.net, cnewburn@nvidia.com, Piotr Luszczek, liakhdi@ornl.gov, Muthu Baskaran, jesmin.jahan.tithi@intel.com, slolivi@sandia.gov, hcedwar@sandia.gov, fuchst@nm.ifi.lmu.de, rbbrigh@sandia.gov

Signed up, but seemed not to make it: timothy.g.mattson@intel.com, schulzm@llnl.gov, oscar@ornl.gov[conflict], mbauer@nvidia.com, romain.e.cledat@intel.com, aiken@cs.stanford.edu, mfarooqi14@ku.edu.tr, lopezmg@ornl.gov, Benoit Meister, vgrover@nvidia.com, kelly.a.livingston@intel.com, alexandr.nigay@inf.ethz.ch, matthieu.schaller@durham.ac.uk, manjugv@ornl.gov, esaule@uncc.edu, roman@icis.pcz.pl, schandra@udel.edu, cychan@lbl.gov, gshipman@lanl.gov, mgarland@nvidia.com, vsarkar@me.com, Didem Unat, maria.garzaran@intel.com, john.feo@pnnl.gov, mike.chu@amd.com, timothee.ewart@epfl.ch, jim@ks.uiuc.edu, n-maruyama@acm.org, pcicotti@sdsc.edu, kk13@rice.edu, srajama@sandia.gov

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)