https://github.com/cevek/slow-code-detector

https://github.com/cevek/slow-code-detector

Last synced: 2 months ago
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• Host: GitHub
• URL: https://github.com/cevek/slow-code-detector
• Owner: cevek
• Created: 2017-01-15T19:29:39.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2018-03-28T15:54:02.000Z (over 6 years ago)
• Last Synced: 2024-10-10T19:07:29.000Z (3 months ago)
• Language: TypeScript
• Size: 27.3 KB
• Stars: 9
• Watchers: 4
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# Slow-Code-Detector

Tool to show slow calls in your code runned by v8.

## Install

`npm i -g slow-code-detector`

## How to use

`scd your-index-js-file.js` – it creates bunch of files in current directory `code.asm` `hydrogen.cfg` `out.txt` `code.html`

`code.html` – is what you need, open it in the browser.

Also you can generate markdown file `code.md`, just run with `--md` option: `scd --md index.js`

Generated `code.html` groupped by files and functions.

## `code.html`

Every runtime call highlighted by gray. Call cost ~4ns.

Pink highlight is LoadGeneric or StoreGeneric. Generic read or write cost ~9ns.

If function in code is inlined it highlighted by blue, you can show its code by click.

If function is not inlined you can show `non inline reason` by a hint on call function name.

If function deoptimized, it colored by red.

Every function reoptimization marked by ~recompile~ – max 10 times, else deopt: `Optimize too many times`

## How it works

The `scd` execute `node` with some v8 trace options and parse given logs to find slow path calls.

`node --trace-inlining --trace-hydrogen --trace-phase=Z --trace-deopt`

## IRHydra

You can use `hydrogen.cfg` and `code.asm` with [IRHydra](http://mrale.ph/irhydra/2/#ir) to investigate internal representation of your code