PulseAugur
EN
LIVE 01:24:35

Python 3.15 Profiler Identifies Line-Ending Preservation as Bottleneck

By PulseAugur Editorial · [1 sources] ·

Simon Willison explored the performance of a web-editing application using Python 3.15's new profiling tools. The analysis revealed that handling mixed line endings, specifically the `preserve_endings` function, was a significant bottleneck, accounting for over 64% of CPU stacks. The profiling also highlighted the importance of sampling all threads, as the majority of performance data originated from AnyIO's worker threads, which would have been missed by a main-thread-only profile. Willison utilized GPT-6 Astra Extra High in Codex to generate flame graphs and heatmaps demonstrating these performance characteristics. AI

IMPACT Highlights the utility of AI models in performance analysis and code optimization for software development.

RANK_REASON The item details research into the performance characteristics of a specific software version using profiling tools. [lever_c_demoted from research: ic=1 ai=0.7]

Read on Simon Willison →

AI-generated summary · Google Gemini · from 1 sources. How we write summaries →

Python 3.15 Profiler Identifies Line-Ending Preservation as Bottleneck

How we ranked this

Signal score
0 / 100
Composite score across the factors below. Higher = stronger signal that this story matters right now.
Newsworthiness bucket
Tool
The item details research into the performance characteristics of a specific software version using profiling tools. [lever_c_demoted from research: ic=1 ai=0.7]
Source corroboration
Single-source cluster
Only one publisher covered this so far. Single-source stories can still rank when the publisher is high-authority, but they lack cross-source corroboration.
Topics
product, infra
Editorial topic classification. Feeds into how the story surfaces on /topic/<slug> hub pages and into the per-entity coverage mix.
AI-industry relevance
High
Clearly on-topic for AI-industry coverage.
Story freshness
4 days old
Aged out of breaking-news scoring windows; ranking reflects the durable signal from the full source set.

Full methodology in our editorial standards.

COVERAGE [1]

  1. Simon Willison TIER_1 English(EN) ·

    Profiling web-edit with Python 3.15: flame graphs and source heatmaps

    <p><strong>Research:</strong> <a href="https://github.com/simonw/research/tree/main/python-3-15-web-edit-profiling#readme">Profiling web-edit with Python 3.15: flame graphs and source heatmaps</a></p> <p>I put the <a href="https://simonwillison.net/2026/Oct/12/python-3-15/#a-samp…

RELATED ENTITIES

RELATED TOPICS