python / python/cpython

Quicken everything

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#98,686 1 comment 0 reactions 1 assignee View on GitHub

@brandtbucher is already working on this.

Since Oct 25, 2022.

3.12 interpreter-core performance
Dominant language
Python
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Description

...as discussed in https://github.com/faster-cpython/ideas/issues/462.

Basically, we can simplify the quickening process by quickening code objects as they are created. This works by ditching our per-code-object warmup counter, and instead using our adaptive backoff counters for more-granular "warming".

I have a branch that implements this change, resulting in consistent a ~1% performance improvement. I imagine that this comes from several places:

  • A lower specialization threshold. I tried a wide range of initial adaptive counter values (ranging from 0 to 4095), and a value of 1 worked best. With this value, adaptive instructions will specialize the second time they are run.
  • A simpler interpreter loop. RESUME_QUICK and JUMP_BACKWARD_QUICK are no longer needed.
  • Superinstructions everywhere. All code objects have superinstructions now.

Next steps will be simplifying the unmarshal / code creation process as part of this same work.

  • PR: gh-98687
  • PR: gh-99106
  • PR: gh-99182
  • PR: gh-99399

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