Resolver perf: Prefer Maps over dynamic objects for normalised exports field (5/n)
#1335
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
facebook-github-bot
added
the
CLA Signed
|
This pull request was exported from Phabricator. Differential Revision: D61850544 |
…ts` field (5/n) (#1335) Summary: Pull Request resolved: #1335 In V8, dynamic objects (that cannot use a hidden class optimisation) are slow - `Map` is both more performant and generally safer. By normalising the `exports` field to a `Map` object (once, as normalisations are cached), subsequent lookup, iteration and reduction is considerably faster, improving `resolvePackageTargetFromExports` around 2x. This is an implementation detail of `PackageExportsResolve.js`, the normalised format is not exposed outside that module. This brings total resolution time for RNTester down below 100ms, vs >1500ms at the beginning of this stack. (I'll allow myself a 🚀 for that). Changelog: ``` - **[Performance]**: Prefer `Map` to dynamic JS objects in package exports resolver. ``` Reviewed By: huntie Differential Revision: D61850544
|
This pull request was exported from Phabricator. Differential Revision: D61850544 |
robhogan
force-pushed
the
export-D61850544
branch
from
77b03f2 to
5a731f8
Compare
|
This pull request has been merged in 5b23317. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Summary:
In V8, dynamic objects (that cannot use a hidden class optimisation) are slow -
Mapis both more performant and generally safer.By normalising the
exportsfield to aMapobject (once, as normalisations are cached), subsequent lookup, iteration and reduction is considerably faster, improvingresolvePackageTargetFromExportsaround 2x.This is an implementation detail of
PackageExportsResolve.js, the normalised format is not exposed outside that module.This brings total resolution time for RNTester down below 100ms, vs >1500ms at the beginning of this stack. (I'll allow myself a 🚀 for that).
Changelog:
Reviewed By: huntie
Differential Revision: D61850544