forked from Zakaria/hermes-agent
Zakaria
104 lines
3.6 KiB
JavaScript
104 lines
3.6 KiB
JavaScript
// CPU-profile a synthetic stream — outputs a .cpuprofile and a top-self ranking.
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// Open the .cpuprofile in Chrome DevTools Performance panel for a flamegraph.
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import { writeFileSync } from 'node:fs'
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const CDP_HTTP = 'http://127.0.0.1:9222'
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const TOKENS = Number(process.env.TOKENS || 400)
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const INTERVAL_MS = Number(process.env.INTERVAL_MS || 8)
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const CHUNK = process.env.CHUNK || '**word** in _italic_ with `code` '
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const LABEL = process.env.LABEL || 'profile'
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const OUT = process.env.OUT || `synth-${LABEL}.cpuprofile`
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class CDP {
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constructor(ws) { this.ws = ws; this.id = 0; this.pending = new Map() }
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static async open(url) {
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const ws = new WebSocket(url)
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await new Promise((r) => ws.addEventListener('open', r, { once: true }))
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const cdp = new CDP(ws)
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ws.addEventListener('message', (ev) => {
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const m = JSON.parse(ev.data.toString())
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if (m.id != null && cdp.pending.has(m.id)) {
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const { resolve, reject } = cdp.pending.get(m.id)
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cdp.pending.delete(m.id)
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if (m.error) reject(new Error(m.error.message))
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else resolve(m.result)
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}
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})
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return cdp
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}
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send(method, params) {
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const id = ++this.id
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return new Promise((res, rej) => {
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this.pending.set(id, { resolve: res, reject: rej })
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this.ws.send(JSON.stringify({ id, method, params }))
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})
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}
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async eval(expr) {
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const r = await this.send('Runtime.evaluate', { expression: expr, returnByValue: true, awaitPromise: true })
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if (r.exceptionDetails) throw new Error(r.exceptionDetails.exception?.description || 'eval')
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return r.result.value
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}
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close() { this.ws.close() }
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}
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async function main() {
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const list = await (await fetch(`${CDP_HTTP}/json`)).json()
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const target = list.find((t) => t.type === 'page' && /5174/.test(t.url))
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const cdp = await CDP.open(target.webSocketDebuggerUrl)
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if (!await cdp.eval('!!window.__PERF_DRIVE__')) {
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console.error('no __PERF_DRIVE__')
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cdp.close()
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process.exit(2)
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}
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await cdp.send('Profiler.enable')
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// High-resolution sampling: 100us
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await cdp.send('Profiler.setSamplingInterval', { interval: 100 })
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await cdp.send('Profiler.start')
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await cdp.eval(`window.__PERF_DRIVE__.stream({ chunk: ${JSON.stringify(CHUNK)}, intervalMs: ${INTERVAL_MS}, totalTokens: ${TOKENS} })`)
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await new Promise((r) => setTimeout(r, TOKENS * INTERVAL_MS + 1500))
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await cdp.eval('window.__PERF_DRIVE__.reset()')
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const { profile } = await cdp.send('Profiler.stop')
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writeFileSync(OUT, JSON.stringify(profile))
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console.log('wrote', OUT)
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// Compute top self time per function.
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const samples = profile.samples || []
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const timeDeltas = profile.timeDeltas || []
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const nodes = new Map(profile.nodes.map((n) => [n.id, n]))
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const selfTime = new Map() // id -> microseconds
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for (let i = 0; i < samples.length; i++) {
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const id = samples[i]
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const dt = timeDeltas[i] ?? 0
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selfTime.set(id, (selfTime.get(id) || 0) + dt)
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}
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const ranked = [...selfTime.entries()]
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.map(([id, us]) => {
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const n = nodes.get(id)
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const cf = n?.callFrame || {}
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return {
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us,
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ms: us / 1000,
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name: cf.functionName || '(anonymous)',
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url: (cf.url || '').slice(-60),
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line: cf.lineNumber
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}
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})
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.filter((x) => !/\(root\)|\(idle\)|\(garbage collector\)|\(program\)/.test(x.name))
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.sort((a, b) => b.us - a.us)
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.slice(0, 30)
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console.log('\n=== TOP 30 SELF TIME (ms) ===')
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for (const r of ranked) {
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console.log(`${r.ms.toFixed(1).padStart(7)} ${r.name.padEnd(40)} ${r.url}:${r.line}`)
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}
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cdp.close()
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}
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main().catch((e) => { console.error(e); process.exit(1) })
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