deoptigate app.js

Jason Miller aka @_developit, creator of preact.	John-David Dalton aka @jdalton, creator of lodash.

Why the New V8 is so Damn Fast

Tracking Down and Fixing Performance Bottlenecks with N|Solid and Deoptigate

npm install -g deoptigate

deoptigate app.js

Override Node.js executable and/or pass it custom arguments

deoptigate -- /bin/mynode app.js

deoptigate -- node --allow-natives-syntax app.js

Simply run deoptigate from the directory that contains the log file(s).

Launch a Chromium-based browser with the necessary tracing flags. For example, running on localhost and writing the log file to the /temp/trace directory:

%browser% --no-sandbox --js-flags="--trace-ic --nologfile-per-isolate --logfile=/temp/trace/v8.log" http://localhost:8000/

When running with no sandbox, you can also load pages directly from disk, e.g.

%browser% --no-sandbox --disable-extensions --js-flags="--trace-ic --nologfile-per-isolate --logfile=/temp/trace/v8.log" c:\temp\trace\default.html

With the directory containing the log file as the current directory, run deoptigate.

Note: The JavaScript files to analyze must be laid out in the current directory as they are in the URL path. For example, if the browser loaded a file at http://localhost:8000/js/app.js above, then the file should exist at /temp/trace/js/app.js. If the local copy does not exist, it will not appear in the analysis.

MIT