Slightly improve perf report

.github/workflows/performance-report.yml

@@ -1,13 +1,12 @@
 name: Performance Report
-env:
-  BUILD_BOOTSTRAP_CJS: mv dist dist-build && node dist-build/bin/rollup --config rollup.config.ts --configPlugin typescript --configTest --forceExit && rm -rf dist-build
 
 on:
-  pull_request:
+  pull_request_target:
     types:
       - synchronize
       - opened
       - reopened
+      - labeled
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
@@ -18,6 +17,7 @@ permissions:
 
 jobs:
   build-artefacts:
+    if: ${{ github.event.pull_request.head.repo.full_name == 'rollup/rollup' || contains( toJson(github.event.pull_request.labels), 'x⁸ ⚙️ build repl artefacts' ) }}
     strategy:
       matrix:
         settings:
@@ -62,7 +62,7 @@ jobs:
         if: steps.cache-node-modules.outputs.cache-hit != 'true'
         run: npm ci --ignore-scripts
       - name: Build artefacts 123
-        run: npm exec -- concurrently -c green,blue 'npm:build:napi -- --release' 'npm:build:cjs' && npm run build:copy-native && ${{env.BUILD_BOOTSTRAP_CJS}} && npm run build:copy-native
+        run: npm exec -- concurrently -c green,blue 'npm:build:napi -- --release' 'npm:build:cjs' && npm run build:copy-native && npm run build:bootstrap:cjs && npm run build:copy-native
       - name: Upload artifact
         uses: actions/upload-artifact@v4
         with:
@@ -73,7 +73,7 @@ jobs:
   report:
     needs: build-artefacts
     permissions:
-      pull-requests: write
+      pull-requests: write # for peter-evans/find-comment and peter-evans/create-or-update-comment
     runs-on: ubuntu-latest
     name: Report Performance
     steps:

package.json

@@ -50,6 +50,7 @@
     "dev": "vitepress dev docs",
     "build:cjs": "rollup --config rollup.config.ts --configPlugin typescript --configTest --forceExit",
     "build:bootstrap": "shx mv dist dist-build && node dist-build/bin/rollup --config rollup.config.ts --configPlugin typescript --forceExit && shx rm -rf dist-build",
+    "build:bootstrap:cjs": "shx mv dist dist-build && node dist-build/bin/rollup --config rollup.config.ts --configPlugin typescript --configTest --forceExit && shx rm -rf dist-build",
     "build:docs": "vitepress build docs",
     "build:ast-converters": "node scripts/generate-ast-converters.js",
     "preview:docs": "vitepress preview docs",
@@ -66,7 +67,7 @@
     "lint:markdown:nofix": "prettier --check \"**/*.md\"",
     "lint:rust": "cd rust && cargo fmt && cargo clippy --fix --allow-dirty",
     "lint:rust:nofix": "cd rust && cargo fmt --check && cargo clippy",
-    "perf": "npm run build && node --expose-gc scripts/perf-report/index.js",
+    "perf": "npm run build:bootstrap:cjs && node --expose-gc scripts/perf-report/index.js",
     "prepare": "husky && node scripts/check-release.js || npm run build:prepare",
     "prepublishOnly": "node scripts/check-release.js && node scripts/prepublish.js",
     "postpublish": "node scripts/postpublish.js",

scripts/perf-report/index.js

@@ -22,9 +22,11 @@ const ENTRY = new URL('entry.js', PERF_DIRECTORY);
 const THREEJS_COPIES = 10;
 const { bold, underline, cyan, red, green } = createColors();
 const MIN_ABSOLUTE_TIME_DEVIATION = 10;
-const RELATIVE_DEVIATION_FOR_COLORING = 5;
-const RUNS_TO_AVERAGE = 5;
-const DISCARDED_RESULTS = 2;
+const MIN_RELATIVE_DEVIATION_PERCENT = 2;
+const RELATIVE_DEVIATION_PERCENT_FOR_COLORING = 5;
+const RUNS_TO_AVERAGE = 7;
+const DISCARDED_LARGE_RESULTS = 2;
+const DISCARDED_SMALL_RESULTS = 1;
 
 await ensureBenchmarkExists();
 await calculatePrintAndPersistTimings();
@@ -62,8 +64,8 @@ async function calculatePrintAndPersistTimings() {
 	console.info(
 		bold(
 			`Comparing against rollup@${previousVersion}.\nCalculating the average of ${cyan(RUNS_TO_AVERAGE)} runs discarding the ${cyan(
-				DISCARDED_RESULTS
-			)} largest results.`
+				DISCARDED_LARGE_RESULTS
+			)} largest and the ${cyan(DISCARDED_SMALL_RESULTS)}s smallest results.`
 		)
 	);
 	chdir(fileURLToPath(PERF_DIRECTORY));
@@ -136,12 +138,14 @@ function getAverage(accumulatedMeasurements, runs) {
 			memory: getSingleAverage(
 				accumulatedMeasurements[label].map(timing => timing[2]),
 				runs,
-				DISCARDED_RESULTS
+				DISCARDED_LARGE_RESULTS,
+				DISCARDED_SMALL_RESULTS
 			),
 			time: getSingleAverage(
 				accumulatedMeasurements[label].map(timing => timing[0]),
 				runs,
-				DISCARDED_RESULTS
+				DISCARDED_LARGE_RESULTS,
+				DISCARDED_SMALL_RESULTS
 			)
 		};
 	}
@@ -151,16 +155,19 @@ function getAverage(accumulatedMeasurements, runs) {
 /**
  * @param {number[]} times
  * @param {number} runs
- * @param {number} discarded
+ * @param {number} discardedLarge
+ * @param {number} discardedSmall
  * @return {number}
  */
-function getSingleAverage(times, runs, discarded) {
-	const actualDiscarded = Math.min(discarded, runs - 1);
+function getSingleAverage(times, runs, discardedLarge, discardedSmall) {
+	const actualDiscarded = Math.min(discardedLarge + discardedSmall, runs - 1);
+	const actualDiscardedSmall = Math.max(actualDiscarded - discardedLarge, 0);
+	const actualDiscardedLarge = actualDiscarded - actualDiscardedSmall;
 	return (
 		times
 			.sort()
 			.reverse()
-			.slice(actualDiscarded)
+			.slice(actualDiscardedLarge, runs - actualDiscardedSmall)
 			.reduce((sum, time) => sum + time, 0) /
 		(runs - actualDiscarded)
 	);
@@ -255,13 +262,16 @@ function getFormattedTime(measuredTime, baseTime = measuredTime) {
 	let color = identity,
 		formattedTime = `${measuredTime.toFixed(0)}ms`;
 	const absoluteDeviation = Math.abs(measuredTime - baseTime);
-	if (absoluteDeviation > MIN_ABSOLUTE_TIME_DEVIATION) {
+	const relativeDeviation = 100 * (absoluteDeviation / baseTime);
+	if (
+		absoluteDeviation > MIN_ABSOLUTE_TIME_DEVIATION &&
+		relativeDeviation > MIN_RELATIVE_DEVIATION_PERCENT
+	) {
 		const sign = measuredTime >= baseTime ? '+' : '-';
-		const relativeDeviation = 100 * (absoluteDeviation / baseTime);
 		formattedTime += ` (${sign}${absoluteDeviation.toFixed(
 			0
 		)}ms, ${sign}${relativeDeviation.toFixed(1)}%)`;
-		if (relativeDeviation > RELATIVE_DEVIATION_FOR_COLORING) {
+		if (relativeDeviation > RELATIVE_DEVIATION_PERCENT_FOR_COLORING) {
 			color = measuredTime >= baseTime ? red : green;
 		}
 	}
@@ -280,11 +290,13 @@ function getFormattedMemory(currentMemory, persistedMemory = currentMemory) {
 	let color = identity,
 		formattedMemory = prettyBytes(currentMemory);
 	const absoluteDeviation = Math.abs(currentMemory - persistedMemory);
-	const sign = currentMemory >= persistedMemory ? '+' : '-';
 	const relativeDeviation = 100 * (absoluteDeviation / persistedMemory);
-	if (relativeDeviation > RELATIVE_DEVIATION_FOR_COLORING) {
+	if (relativeDeviation > MIN_RELATIVE_DEVIATION_PERCENT) {
+		const sign = currentMemory >= persistedMemory ? '+' : '-';
 		formattedMemory += ` (${sign}${relativeDeviation.toFixed(0)}%)`;
-		color = currentMemory >= persistedMemory ? red : green;
+		if (relativeDeviation > RELATIVE_DEVIATION_PERCENT_FOR_COLORING) {
+			color = currentMemory >= persistedMemory ? red : green;
+		}
 	}
 	return color(formattedMemory);
 }

scripts/perf-report/report-collector.js

@@ -15,8 +15,14 @@ export default new (class ReportCollector {
 	 */
 	push(message) {
 		if (!this.#isRecording) return;
-		if (message.startsWith('#')) {
-			message = '##' + message;
+		if (message.startsWith('# ')) {
+			message = message.replace(/^# /, '- ');
+		} else if (message.startsWith('## ')) {
+			message = message.replace(/^## /, '  - ');
+		} else if (message.startsWith('- ')) {
+			message = '      ' + message;
+		} else {
+			message = '    - ' + message;
 		}
 		this.#messageList.push(message);
 	}

src/utils/timers.ts

@@ -18,7 +18,9 @@ interface Timer {
 
 let timers = new Map<string, Timer>();
 
-function getPersistedLabel(label: string, level: number): string {
+type LabelLevel = 1 | 2 | 3 | 4;
+
+function getPersistedLabel(label: string, level: LabelLevel): string {
 	switch (level) {
 		case 1: {
 			return `# ${label}`;
@@ -30,12 +32,12 @@ function getPersistedLabel(label: string, level: number): string {
 			return label;
 		}
 		default: {
-			return `${'  '.repeat(level - 4)}- ${label}`;
+			return `- ${label}`;
 		}
 	}
 }
 
-function timeStartImpl(label: string, level = 3): void {
+function timeStartImpl(label: string, level: LabelLevel = 3): void {
 	label = getPersistedLabel(label, level);
 
 	const startMemory = process.memoryUsage().heapUsed;
@@ -57,7 +59,7 @@ function timeStartImpl(label: string, level = 3): void {
 	}
 }
 
-function timeEndImpl(label: string, level = 3): void {
+function timeEndImpl(label: string, level: LabelLevel = 3): void {
 	label = getPersistedLabel(label, level);
 
 	const timer = timers.get(label);
@@ -79,8 +81,8 @@ export function getTimings(): SerializedTimings {
 	return newTimings;
 }
 
-export let timeStart: (label: string, level?: number) => void = doNothing;
-export let timeEnd: (label: string, level?: number) => void = doNothing;
+export let timeStart: (label: string, level?: LabelLevel) => void = doNothing;
+export let timeEnd: (label: string, level?: LabelLevel) => void = doNothing;
 
 const TIMED_PLUGIN_HOOKS: readonly (keyof PluginHooks)[] = [
 	'augmentChunkHash',