From c40ab1114f4d1d887a970f74e9cd84975dd63d52 Mon Sep 17 00:00:00 2001
From: tsctx <91457664+tsctx@users.noreply.github.com>
Date: Mon, 19 Feb 2024 20:54:09 +0900
Subject: [PATCH] chore: update headers iterator benchmark

---
 benchmarks/headers.mjs                | 56 +++++++++++++++++----------
 lib/fetch/headers.js                  |  1 +
 test/fetch/headerslist-sortedarray.js |  4 +-
 3 files changed, 38 insertions(+), 23 deletions(-)

diff --git a/benchmarks/headers.mjs b/benchmarks/headers.mjs
index 2b3bc985c65..545d3f2bd8f 100644
--- a/benchmarks/headers.mjs
+++ b/benchmarks/headers.mjs
@@ -1,4 +1,4 @@
-import { bench, run } from 'mitata'
+import { bench, group, run } from 'mitata'
 import { Headers } from '../lib/fetch/headers.js'
 
 const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
@@ -12,32 +12,46 @@ function generateAsciiString (length) {
   return result
 }
 
-const headers = new Headers(
-  Array.from(Array(32), () => generateAsciiString(12)).map((v) => [v, ''])
-)
+const settings = {
+  'fast-path (tiny array)': 4,
+  'fast-path (small array)': 8,
+  'fast-path (middle array)': 16,
+  'fast-path': 32,
+  'slow-patch': 64
+}
+
+for (const [name, length] of Object.entries(settings)) {
+  const headers = new Headers(
+    Array.from(Array(length), () => [generateAsciiString(12), ''])
+  )
 
-const headersSorted = new Headers(headers)
+  const headersSorted = new Headers(headers)
 
-const kHeadersList = Reflect.ownKeys(headers).find(c => String(c) === 'Symbol(headers list)')
+  const kHeadersList = Reflect.ownKeys(headers).find(
+    (c) => String(c) === 'Symbol(headers list)'
+  )
 
-const headersList = headers[kHeadersList]
+  const headersList = headers[kHeadersList]
 
-const headersListSorted = headersSorted[kHeadersList]
+  const headersListSorted = headersSorted[kHeadersList]
 
-const kHeadersSortedMap = Reflect.ownKeys(headersList).find(
-  (c) => String(c) === 'Symbol(headers map sorted)'
-)
+  const kHeadersSortedMap = Reflect.ownKeys(headersList).find(
+    (c) => String(c) === 'Symbol(headers map sorted)'
+  )
 
-bench('Headers@@iterator', () => {
-  // prevention of memoization of results
-  headersList[kHeadersSortedMap] = null
-  return [...headers]
-})
+  group(`length ${length} #${name}`, () => {
+    bench('Headers@@iterator', () => {
+      // prevention of memoization of results
+      headersList[kHeadersSortedMap] = null
+      return [...headers]
+    })
 
-bench('Headers@@iterator (sorted)', () => {
-  // prevention of memoization of results
-  headersListSorted[kHeadersSortedMap] = null
-  return [...headersSorted]
-})
+    bench('Headers@@iterator (sorted)', () => {
+      // prevention of memoization of results
+      headersListSorted[kHeadersSortedMap] = null
+      return [...headersSorted]
+    })
+  })
+}
 
 await run()
diff --git a/lib/fetch/headers.js b/lib/fetch/headers.js
index f904ca45e06..423cde0c4e9 100644
--- a/lib/fetch/headers.js
+++ b/lib/fetch/headers.js
@@ -290,6 +290,7 @@ class HeadersList {
         // binary search
         while (left < right) {
           pivot = left + ((right - left) >> 1)
+          // compare header name
           if (array[pivot][0] <= x[0]) {
             left = pivot + 1
           } else {
diff --git a/test/fetch/headerslist-sortedarray.js b/test/fetch/headerslist-sortedarray.js
index eee9a546a14..d579e54bdd7 100644
--- a/test/fetch/headerslist-sortedarray.js
+++ b/test/fetch/headerslist-sortedarray.js
@@ -19,7 +19,7 @@ test('toSortedArray (fast-path)', () => {
   for (let i = 0; i < 1000; ++i) {
     const headersList = new HeadersList()
     for (let j = 0; j < 32; ++j) {
-      headersList.append(generateAsciiString(8), generateAsciiString(3))
+      headersList.append(generateAsciiString(4), generateAsciiString(4))
     }
     assert.deepStrictEqual(headersList.toSortedArray(), [...headersList].sort(compareHeaderName))
   }
@@ -30,7 +30,7 @@ test('toSortedArray (slow-path)', () => {
   for (let i = 0; i < 1000; ++i) {
     const headersList = new HeadersList()
     for (let j = 0; j < 64; ++j) {
-      headersList.append(generateAsciiString(8), generateAsciiString(3))
+      headersList.append(generateAsciiString(4), generateAsciiString(4))
     }
     assert.deepStrictEqual(headersList.toSortedArray(), [...headersList].sort(compareHeaderName))
   }