`node:perf_hooks`

Node's [perf_hooks][nodejs-perf-hooks] module surface, importable through both ESM and CommonJS:

import perf from "node:perf_hooks";
// or
const perf = require("node:perf_hooks");

[nodejs-perf-hooks]: https://nodejs.org/api/perf_hooks.html

The module shares its per-realm performance timeline with globalThis.performance: a mark created through one is observable through the other, and perf.performance is identical (===) to globalThis.performance.

Exports

Export	Type	Notes
`performance`	`Performance`	The same singleton as `globalThis.performance`.
`now()`	`() => number`	Equivalent to `performance.now()`.
`mark(name, options?)`	`(name, opts) => PerformanceMark`	Equivalent to `performance.mark`.
`measure(name, startOrOptions?, endMark?)`	`(...) => PerformanceMeasure`	Equivalent to `performance.measure`.
`getEntries()`	`() => PerformanceEntry[]`	Equivalent to `performance.getEntries`.
`getEntriesByName(name, type?)`	`(...) => PerformanceEntry[]`	Equivalent to `performance.getEntriesByName`.
`getEntriesByType(type)`	`(type) => PerformanceEntry[]`	Equivalent to `performance.getEntriesByType`.
`clearMarks(name?)`	`(name?) => void`	Equivalent to `performance.clearMarks`.
`clearMeasures(name?)`	`(name?) => void`	Equivalent to `performance.clearMeasures`.
`timeOrigin`	`number`	Same value as `performance.timeOrigin`.
`nodeTiming`	`PerformanceNodeTiming`	See below. `[SameObject]`.
`PerformanceEntry`	constructor	Same identity as `globalThis.PerformanceEntry`.
`PerformanceMark`	constructor	Same identity as `globalThis.PerformanceMark`.
`PerformanceMeasure`	constructor	Same identity as `globalThis.PerformanceMeasure`.
`PerformanceObserver`	constructor	Same identity as `globalThis.PerformanceObserver`.
`PerformanceObserverEntryList`	constructor	Same identity as `globalThis.PerformanceObserverEntryList`.
`PerformanceNodeTiming`	constructor	Node-only entry constructor; not exposed as a global.
`constants`	object	Empty placeholder — Node ships an empty object here for users who run `Object.keys(perf_hooks).includes('constants')`.

For the full semantics of each entry / observer interface, see the Performance reference. What follows is the Node-only addition.

`PerformanceNodeTiming`

Extends PerformanceEntry (entryType = "node", name = "node"). Captures realm-startup moments. Returned by perf_hooks.performance.nodeTiming. The same instance is referenced across reads ([SameObject]); it also appears in performance.getEntriesByType("node").

interface PerformanceNodeTiming extends PerformanceEntry {
  readonly nodeStart: number;
  readonly v8Start: number;
  readonly environment: number;
  readonly bootstrapComplete: number;
  readonly loopStart: number;
  readonly loopExit: number;
  readonly idleTime: number;
}

In Elide:

Field	Value	Reason
`nodeStart`	`performance.timeOrigin`	The closest analogue to "process start" available; captured at agent init.
`v8Start`	`0`	Truffle JS, not V8 — the field exists for compatibility but has no meaningful value here.
`environment`	`performance.timeOrigin`	The JS environment finishes initialising synchronously alongside the agent.
`bootstrapComplete`	`performance.timeOrigin`	Same — bootstrap is synchronous.
`loopStart`	`0`	The embedder does not surface a discrete event-loop start moment.
`loopExit`	`0`	The loop has not exited yet for the lifetime of the realm.
`idleTime`	`0`	The embedder does not measure event-loop idleness.

The entry itself is constructed lazily on first read of nodeTiming — its values are static once captured, so a delayed first read does not lose information.

Compatibility with Node

require("node:perf_hooks").performance === globalThis.performance — yes, just like Node.
Constructors imported via the module are the same identity as the global ones — values produced one way are instanceof the other.
Async observer-callback delivery uses Elide's microtask checkpoint hook, matching the observable behaviour of Node's promise-microtask-bound delivery.
The legacy monitorEventLoopDelay / createHistogram / PerformanceResourceTiming surfaces are not implemented — the WebIDL source describes only the namespace members listed above.