Hey! 👋 When investigating cloudflare/workers-sdk#4409, I observed that CPU profiles from workerd contain a single (program) entry for the entire duration of the profile. To reproduce this...
# config.capnp
using Workerd = import "/workerd/workerd.capnp";
const config :Workerd.Config = (
services = [
( name = "main", worker = .worker ),
],
sockets = [
( name = "http", address = "*:8080", http = (), service = "main" ),
]
);
const worker :Workerd.Worker = (
modules = [
( name = "./index.mjs", esModule = embed "index.mjs" )
],
compatibilityDate = "2024-01-01",
compatibilityFlags = ["nodejs_compat"],
);// index.mjs
import { Buffer } from "node:buffer";
const encoder = new TextEncoder();
async function pbkdf2Derive(password) {
const passwordArray = encoder.encode(password);
const passwordKey = await crypto.subtle.importKey(
"raw", passwordArray, "PBKDF2", false, ["deriveBits"]
);
const saltArray = crypto.getRandomValues(new Uint8Array(16));
const keyBuffer = await crypto.subtle.deriveBits(
{ name: "PBKDF2", hash: "SHA-256", salt: saltArray, iterations: 1_000_000 },
passwordKey, 256
);
return Buffer.from(keyBuffer).toString("base64");
}
export default {
async fetch(request, env, ctx) {
return new Response(await pbkdf2Derive("hello!"));
}
}// stress.mjs
const total = 1_000;
for (let i = 0; i < total; i++) {
const response = await fetch("http://127.0.0.1:8080");
await response.arrayBuffer();
if (i % 10 === 0) console.log(`${(i * 100 / total).toFixed(0)}%`);
}...then run...
$ npx workerd serve config.capnp --verbose --control-fd=1 --watch --inspector-addr=127.0.0.1:9229 &
$ node stress.mjs
...then visit chrome://inspect to open DevTools and start a CPU profile for a few seconds. For me, the result looks something like...
If I run the following similar code in Node directly with node --inspect-brk index-node.mjs, visit chrome://inspect and start a CPU profile I see something like...
// index-node.mjs
import { Buffer } from "node:buffer";
import { webcrypto as crypto } from "node:crypto";
const encoder = new TextEncoder();
async function pbkdf2Derive(password) {
const passwordArray = encoder.encode(password);
const passwordKey = await crypto.subtle.importKey(
"raw", passwordArray, "PBKDF2", false, ["deriveBits"]
);
const saltArray = crypto.getRandomValues(new Uint8Array(16));
const keyBuffer = await crypto.subtle.deriveBits(
{ name: "PBKDF2", hash: "SHA-256", salt: saltArray, iterations: 1_000_000 },
passwordKey, 256
);
return Buffer.from(keyBuffer).toString("base64");
}
const total = 1_000;
for (let i = 0; i < total; i++) {
console.log(await pbkdf2Derive("hello!"));
if (i % 10 === 0) console.log(`${(i * 100 / total).toFixed(0)}%`);
}
I get that Node probably implements more of these APIs in JavaScript, hence the deeper flame graphs, but I'd still expect to see pbkdf2Dervie() in the workerd profile's flame graph.
Hey! 👋 When investigating cloudflare/workers-sdk#4409, I observed that CPU profiles from
workerdcontain a single(program)entry for the entire duration of the profile. To reproduce this......then run...
$ npx workerd serve config.capnp --verbose --control-fd=1 --watch --inspector-addr=127.0.0.1:9229 & $ node stress.mjs...then visit
chrome://inspectto open DevTools and start a CPU profile for a few seconds. For me, the result looks something like...If I run the following similar code in Node directly with
node --inspect-brk index-node.mjs, visitchrome://inspectand start a CPU profile I see something like...I get that Node probably implements more of these APIs in JavaScript, hence the deeper flame graphs, but I'd still expect to see
pbkdf2Dervie()in theworkerdprofile's flame graph.