Minutes_2021_08_03

Numba Meeting: 2021-08-03

Attendees: Siu Kwan Lam, Todd Anderson, brandon willard, Graham Markall, Lehman Garrison, stuart, Jim Pivarski, Luk

NOTE: All communication is subject to the Numba Code of Conduct.

PSA:
- Job postings category https://numba.discourse.group/c/community/job-postings/14
Exposing control over optimization in pipeline: req discussed in Discourse
- Q: How to expose fine-grain control over optimization? (related post)
- Ideas:
  - Allow user to pass in MPM?
  - 0-10 optimisation level arg for functions
  - Suggest user creates their own higher-optimization effort JIT
  - Or start at aggressively optimize and let user turn it down.
  - Genetic Algorithm for pass selection (Stuart has a prototype)
    - is observed to sometimes outperform O3
- Side Questions:
  - Q: Why multiple passes of optimizations; e.g. "cheap", then "refct", then "expensive"?
  - A: We have "refct" pass to remove atomic reference count operations, which can block aggressive loop optimizations in "expensive" pass. The "refct" pass does best when the IR is inlined and simplified by the "cheap" pass.
Perf hack: https://gist.github.com/sklam/30c2ff32ac72be197a349e6c4e1f5d32

Request for 0.55
- broadcast_to https://github.com/numba/numba/pull/7119
  - driven by need for vectorize support in aesara