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Title: lib: avoid quadratic shift() in startup snapshot callback by watilde · Pull Request #62914 · nodejs/node · GitHub

Open Graph Title: lib: avoid quadratic shift() in startup snapshot callback by watilde · Pull Request #62914 · nodejs/node

X Title: lib: avoid quadratic shift() in startup snapshot callback by watilde · Pull Request #62914 · nodejs/node

Description: Micro benchmark $ cat bench-startup-snapshot-callbacks.js 'use strict'; function runWithShift(callbacks) { while (callbacks.length > 0) { const { 0: cb, 1: data } = callbacks.shift(); cb(data); } } function runWithIndex(callbacks) { for (let i = 0; i < callbacks.length; i++) { const { 0: cb, 1: data } = callbacks[i]; cb(data); } callbacks.length = 0; } function makeCallbacks(count) { return Array.from({ length: count }, (_, j) => [() => {}, j]); } function measure(fn, count, iterations) { // warmup for (let i = 0; i < 50; i++) fn(makeCallbacks(count)); const start = performance.now(); for (let i = 0; i < iterations; i++) fn(makeCallbacks(count)); return performance.now() - start; } const COUNTS = [10, 100, 1_000, 10_000, 100_000]; console.log('--- shift() vs for+length=0 ---\n'); for (const count of COUNTS) { const iters = Math.max(10, Math.floor(1_000_000 / count)); const shiftMs = measure(runWithShift, count, iters); const indexMs = measure(runWithIndex, count, iters); const ratio = shiftMs / indexMs; const countStr = `count=${String(count).padStart(6)}`; const shiftStr = `${shiftMs.toFixed(2).padStart(10)}ms`; const indexStr = `${indexMs.toFixed(2).padStart(8)}ms`; const ratioStr = `${ratio.toFixed(ratio >= 10 ? 0 : 1).padStart(5)}x faster`; console.log(`${countStr} ${shiftStr} vs ${indexStr} => ${ratioStr}`); } Result $ ./node bench-startup-snapshot-callbacks.js --- shift() vs for+length=0 --- count= 10 58.22ms vs 49.66ms => 1.2x faster count= 100 42.62ms vs 32.54ms => 1.3x faster count= 1000 53.96ms vs 30.92ms => 1.7x faster count= 10000 60.50ms vs 28.47ms => 2.1x faster count=100000 46747.20ms vs 50.64ms => 923x faster

Open Graph Description: Micro benchmark $ cat bench-startup-snapshot-callbacks.js 'use strict'; function runWithShift(callbacks) { while (callbacks.length > 0) { const { 0: cb, 1: data } = callbacks.shif...

X Description: Micro benchmark $ cat bench-startup-snapshot-callbacks.js &#39;use strict&#39;; function runWithShift(callbacks) { while (callbacks.length &gt; 0) { const { 0: cb, 1: data } = ca...

Opengraph URL: https://github.com/nodejs/node/pull/62914

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