https://github.com/typescript-eslint/performance
Various performance baselines for typescript-eslint.
https://github.com/typescript-eslint/performance
Last synced: 5 months ago
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Various performance baselines for typescript-eslint.
- Host: GitHub
- URL: https://github.com/typescript-eslint/performance
- Owner: typescript-eslint
- License: mit
- Created: 2024-07-11T13:25:36.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2025-05-21T12:38:24.000Z (6 months ago)
- Last Synced: 2025-06-22T06:06:48.337Z (5 months ago)
- Language: TypeScript
- Homepage:
- Size: 4.03 MB
- Stars: 5
- Watchers: 1
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Contributing: .github/CONTRIBUTING.md
- License: LICENSE.md
- Code of conduct: .github/CODE_OF_CONDUCT.md
- Security: .github/SECURITY.md
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README
typescript-eslint Performance Comparisons
Various performance baselines for typescript-eslint.
## Usage
You'll need [hyperfine](https://github.com/sharkdp/hyperfine) installed locally, such as with `brew install hyperfine` or `winget install hyperfine`.
See [sharkdp/hyperfine#installation](https://github.com/sharkdp/hyperfine#installation).
```shell
npm install
npm run generate
npm run measure
```
You can manually measure individual cases by running `hyperfine ../../node_modules/eslint/bin/eslint.js --ignore-failure --warmup 1`.
### Measured Attributes
The `caseEntries` values in `src/data.ts` can be modified to test:
- `files`: roughly how many generated files should be linted
- `layout`: what rough shape of imports those files exhibit:
- `"even"`: a single root-level `index.ts` importing from roughly an even triangle shape of files
- `"references"`: a single root-level `tsconfig.json` with project references to a few projects
- `"wide"`: one root-level `index.ts` importing from all files in the project
- `singleRun`: whether to enable [single-run inference](https://v8--typescript-eslint.netlify.app/packages/parser#disallowautomaticsingleruninference) as a performance boost
- `types`: whether to use `parserOptions.project` or `parserOptions.projectService` for typed linting
## Results
Right now, `parserOptions.project` _with_ single-run inference outperforms `parserOptions.projectService`.
This is a performance issue and we are investigating it as a bug.
```plaintext
┌───────┬───────────────────────┬───────────────────────┐
│ files │ project (even layout) │ service (even layout) │
┼───────┼───────────────────────┼───────────────────────┤
│ 1024 │ '1.750 s ± 0.008 s' │ '2.473 s ± 0.011 s' │
┴───────┴───────────────────────┴───────────────────────┘
```
See [typescript-eslint/typescript-eslint#9571 Performance: parserOptions.projectService no longer outperforms parserOptions.project](https://github.com/typescript-eslint/typescript-eslint/issues/9571) in typescript-eslint.
Also see the 📌 pinned issues later in this file.
### Result Measurement Notes
- Example measurements taken on an M1 Max Mac Studio with Node.js 22.4.1
- These results are similar across TypeScript versions: 5.0.4, 5.4.5, and 5.5.3
## Traces
The `traces/` directory contains more specific traces for investigations.
> ✨ You might consider using [0x](https://github.com/davidmarkclements/0x) for nice flamegraph visuals.
All comparisons were run on a common shape of linting: 1024 files with the "even" (triangle-shaped) imports layout.
### Comparison: Globals in Scopes
> 📌 Filed on typescript-eslint as [⚡ Performance: Overhead of populateGlobalsFromLib in scope-manager](https://github.com/typescript-eslint/typescript-eslint/issues/9575).
This trace shows the impact of `@typescript-eslint/scope-manager`'s `populateGlobalsFromLib`.
See `traces/globals-scope-manager/`:
- `baseline.cpuprofile`: Baseline measurement with no changes
- `skipping.cpuprofile`: Commenting out the contents of `populateGlobalsFromLib`
They were generated with:
```shell
cd files-1024-layout-even-singlerun-true-types-service
node --cpu-prof --cpu-prof-interval=100 --cpu-prof-name=baseline.cpuprofile ../../node_modules/eslint/bin/eslint.js
# clear ../../node_modules/@typescript-eslint/scope-manager/dist/referencer/Referencer.js > populateGlobalsFromLib
node --cpu-prof --cpu-prof-interval=100 --cpu-prof-name=skipping.cpuprofile ../../node_modules/eslint/bin/eslint.js
```
Hyperfine measurements show a ~20% improvement in lint time:
| Variant | Measurement | User Time |
| -------- | ----------------- | --------- |
| Baseline | 3.137 s ± 0.024 s | 4.417 s |
| Skipping | 2.477 s ± 0.014 s | 3.501 s |
### Comparison: Project and Project Service
This is a preliminary trace to start debugging their differences.
See `traces/Project 1 - Service 2.cpuprofile`.
- Trace #1: `parserOptions.project`
- Trace #2: `parserOptions.projectService`
It was generated with:
```shell
cd cases/files-1024-layout-even-singlerun-true-types-project
node --inspect-brk ../../node_modules/eslint/bin/eslint.js
cd ../files-1024-layout-even-singlerun-true-types-service
node --inspect-brk ../../node_modules/eslint/bin/eslint.js
```
Comparing equivalent code paths:
| Code Path | Project | Service |
| ----------------- | ------- | ------- |
| All `verifyText`s | 2040ms | 2859ms |
| `parseForESLint` | 993ms | 1090ms |
### Comparison: Project Service Client File Cleanups
> 📌 Filed on TypeScript as [⚡ Performance: Project service spends excess time cleaning client files when called synchronously](https://github.com/microsoft/TypeScript/issues/59335).
This comparison shows the cost of the TypeScript project service calling `cleanupProjectsAndScriptInfos`.
See `traces/service-file-cleanup/`:
- `baseline.cpuprofile`: Baseline measurement with no changes
- `skipping.cpuprofile`: Commenting out the contents of TypeScript's `cleanupProjectsAndScriptInfos`
They were generated with:
```shell
cd files-1024-layout-even-singlerun-true-types-service
node --cpu-prof --cpu-prof-interval=100 --cpu-prof-name=baseline.cpuprofile ../../node_modules/eslint/bin/eslint.js
# clear ../../node_modules/typescript/lib/typescript.js > cleanupProjectsAndScriptInfos
node --cpu-prof --cpu-prof-interval=100 --cpu-prof-name=skipping.cpuprofile ../../node_modules/eslint/bin/eslint.js
```
Hyperfine measurements show a ~15-20% improvement in lint time:
| Variant | Measurement | User Time |
| -------- | ----------------- | --------- |
| Baseline | 3.215 s ± 0.041 s | 4.483 s |
| Skipping | 2.501 s ± 0.017 s | 3.758 s |
### Comparison: Project Service Uncached File System Stats
> 📌 Filed on TypeScript as [⚡ Performance: Project service doesn't cache all fs.statSync](https://github.com/microsoft/TypeScript/issues/59338).
This comparison shows the cost uncached `fs.statSync` calls inside the project service.
See `traces/service-uncached-stats/`:
- `baseline.cpuprofile`: Baseline measurement with no changes
- `caching.cpuprofile`: Adding a caching `Map` to TypeScript's `statSync`
They were generated with:
```shell
cd files-1024-layout-even-singlerun-true-types-service
node --cpu-prof --cpu-prof-interval=100 --cpu-prof-name=baseline.cpuprofile ../../node_modules/eslint/bin/eslint.js
# edit ../../node_modules/typescript/lib/typescript.js > statSync (see diff below)
node --cpu-prof --cpu-prof-interval=100 --cpu-prof-name=caching.cpuprofile ../../node_modules/eslint/bin/eslint.js
```
diff patch to switch to the Caching variant...
```diff
diff --git a/node_modules/typescript/lib/typescript.js b/node_modules/typescript/lib/typescript.js
index 4baad59..44639d5 100644
--- a/node_modules/typescript/lib/typescript.js
+++ b/node_modules/typescript/lib/typescript.js
@@ -8546,9 +8546,15 @@ var sys = (() => {
}
}
};
+ const statCache = new Map();
return nodeSystem;
function statSync(path) {
- return _fs.statSync(path, { throwIfNoEntry: false });
+ if (statCache.has(path)) {
+ return statCache.get(path);
+ }
+ const result = _fs.statSync(path, { throwIfNoEntry: false });
+ statCache.set(path, result);
+ return result;
}
function enableCPUProfiler(path, cb) {
if (activeSession) {
```
Hyperfine measurements show a ~7-12% improvement in lint time:
| Variant | Measurement | User Time |
| -------- | ----------------- | --------- |
| Baseline | 3.112 s ± 0.033 s | 4.382 |
| Caching | 2.740 s ± 0.030 s | 4.032 |
### Comparison: Project Service Uncached File System Path Reads
> 📌 Filed on TypeScript as [⚡ Performance: Project service doesn't cache all fs.realpath](https://github.com/microsoft/TypeScript/issues/59342).
This comparison shows the cost uncached `fs.realpath` calls inside the project service.
See `traces/service-uncached-realpaths/`:
- `baseline.cpuprofile`: Baseline measurement with no changes
- `caching.cpuprofile`: Adding a caching `Map` to TypeScript's `realpath`
They were generated with:
```shell
cd files-1024-layout-even-singlerun-true-types-service
node --cpu-prof --cpu-prof-interval=100 --cpu-prof-name=baseline.cpuprofile ../../node_modules/eslint/bin/eslint.js
# edit ../../node_modules/typescript/lib/typescript.js > realpath (see diff below)
node --cpu-prof --cpu-prof-interval=100 --cpu-prof-name=caching.cpuprofile ../../node_modules/eslint/bin/eslint.js
```
diff patch to switch to the Caching variant...
```diff
diff --git a/node_modules/typescript/lib/typescript.js b/node_modules/typescript/lib/typescript.js
index 4baad59..e53476d 100644
--- a/node_modules/typescript/lib/typescript.js
+++ b/node_modules/typescript/lib/typescript.js
@@ -13,6 +13,8 @@ See the Apache Version 2.0 License for specific language governing permissions
and limitations under the License.
***************************************************************************** */
+var realpathCache = new Map();
+
var ts = {}; ((module) => {
"use strict";
var __defProp = Object.defineProperty;
@@ -8798,6 +8800,15 @@ var sys = (() => {
return path.length < 260 ? _fs.realpathSync.native(path) : _fs.realpathSync(path);
}
function realpath(path) {
+ const cached = realpathCache.get(path);
+ if (cached) {
+ return cached;
+ }
+ const result = realpathWorker(path);
+ realpathCache.set(path, result);
+ return result;
+ }
+ function realpathWorker(path) {
try {
return fsRealpath(path);
} catch {
```
Hyperfine measurements with `--runs 50` show a ~0.5-2.5% improvement in lint time:
| Variant | Measurement | User Time |
| -------- | ----------------- | --------- |
| Baseline | 3.153 s ± 0.039 s | 4.403 s |
| Caching | 3.073 s ± 0.048 s | 4.377 s |
## Contributors
