dtolnay/ryu

Investigate faster performance than upstream implementation

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#35 opened on Oct 2, 2020

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help wanted

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Description

As observed in https://github.com/dtolnay/ryu/pull/34#issue-496690273, the 32-bit and 64-bit float-to-string benchmark in this repo is something like 40% faster than the exact same benchmark in https://github.com/ulfjack/ryu. We need to examine whether there is any inadvertent discrepancy between the two benchmarks, difference in build configuration, or any toolchain difference that would account for this. The code is a line-by-line transliteration so there should really be no performance difference, and certainly not this big.

Contributor guide

Research direction
Compare benchmark configurations (e.g., compiler flags, optimization settings) between the two repositories. Check if there are any differences in the benchmark harness, such as iteration counts or measurement overhead. Verify that the compiled code is identical by examining assembly output. Look for toolchain version differences (e.g., Rust compiler version) that might explain the performance gap.
Tech stack
rust
Domain
backendperformance
Issue type
Research
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
RustBenchmarking
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30