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svelte/benchmarking/utils.js

99 lines
2.3 KiB

import { performance, PerformanceObserver } from 'node:perf_hooks';
import v8 from 'v8-natives';
// Credit to https://github.com/milomg/js-reactivity-benchmark for the logic for timing + GC tracking.
class GarbageTrack {
track_id = 0;
observer = new PerformanceObserver((list) => this.perf_entries.push(...list.getEntries()));
perf_entries = [];
periods = [];
watch(fn) {
this.track_id++;
const start = performance.now();
const result = fn();
const end = performance.now();
this.periods.push({ track_id: this.track_id, start, end });
return { result, track_id: this.track_id };
}
/**
* @param {number} track_id
*/
async gcDuration(track_id) {
await promise_delay(10);
const period = this.periods.find((period) => period.track_id === track_id);
if (!period) {
// eslint-disable-next-line @typescript-eslint/prefer-promise-reject-errors
return Promise.reject('no period found');
}
const entries = this.perf_entries.filter(
(e) => e.startTime >= period.start && e.startTime < period.end
);
return entries.reduce((t, e) => e.duration + t, 0);
}
destroy() {
this.observer.disconnect();
}
constructor() {
this.observer.observe({ entryTypes: ['gc'] });
}
}
function promise_delay(timeout = 0) {
return new Promise((resolve) => setTimeout(resolve, timeout));
}
/**
* @param {{ (): void; (): any; }} fn
*/
function run_timed(fn) {
const start = performance.now();
const result = fn();
const time = performance.now() - start;
return { result, time };
}
/**
* @param {() => void} fn
*/
async function run_tracked(fn) {
v8.collectGarbage();
const gc_track = new GarbageTrack();
const { result: wrappedResult, track_id } = gc_track.watch(() => run_timed(fn));
const gc_time = await gc_track.gcDuration(track_id);
const { result, time } = wrappedResult;
gc_track.destroy();
return { result, timing: { time, gc_time } };
}
/**
* @param {number} times
* @param {() => void} fn
*/
export async function fastest_test(times, fn) {
const results = [];
for (let i = 0; i < times; i++) {
const run = await run_tracked(fn);
results.push(run);
}
const fastest = results.reduce((a, b) => (a.timing.time < b.timing.time ? a : b));
return fastest;
}
/**
* @param {boolean} a
*/
export function assert(a) {
if (!a) {
throw new Error('Assertion failed');
}
}