rayon-rs/rayon

idea: allow control of splitting depth / number of jobs

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#476 opened on Nov 17, 2017

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 (2 comments) (0 reactions) (0 assignees)Rust (9,410 stars) (450 forks)batch import
enhancementhelp wanted

Description

We currently have with_min_len and with_max_len to control the length of the split iterators. However, this only works on an IndexedParallelIterator that knows its length in the first place.

Perhaps we could offer different controls for the splitting depth, or the number of jobs (~2depth), which could work on any parallel iterator. This may line up more directly to how folks think about their tasks, especially if they want to split exactly into the number of threads.

Contributor guide

Tech stack
rust
Domain
backendperformance
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
RustRayon parallel iteratorssplitting concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
15
Research direction
Examine the implementation of `with min len` and `with max len` in the Rayon source (likely in `src/iter/plumbing.rs` or similar). Understand how splitting currently works for non indexed iterators. Consider the design of a new method to control splitting depth, potentially by adding a parameter to the `splitter` or `producer` traits. Review the two comments on the issue for additional context.