11 Node.js-specific performance measurements.
20 const { PerformanceObserver, performance } = require('perf_hooks');
24   performance.clearMarks();
27 performance.measure('Start to Now');
29 performance.mark('A');
31   performance.measure('A to Now', 'A');
33   performance.mark('B');
34   performance.measure('A to B', 'A', 'B');
38 ## `perf_hooks.performance`
43 An object that can be used to collect performance metrics from the current
44 Node.js instance. It is similar to [`window.performance`][] in browsers.
46 ### `performance.clearMarks([name])`  argument
56 ### `performance.eventLoopUtilization([utilization1[, utilization2]])`  argument
100 const { eventLoopUtilization } = require('perf_hooks').performance;
118 ### `performance.mark([name])`  argument
131 ### `performance.measure(name[, startMark[, endMark]])`  argument
157 `PerformanceNodeTiming` class. `endMark` will be `performance.now()`
161 ### `performance.nodeTiming`  argument
170 An instance of the `PerformanceNodeTiming` class that provides performance
173 ### `performance.now()`  argument
183 ### `performance.timeOrigin`  argument
193 ### `performance.timerify(fn)`  argument
208   performance,
216 const wrapped = performance.timerify(someFunction);
224 // A performance timeline entry will be created
250 The type of the performance entry. It may be one of:
271 When `performanceEntry.entryType` is equal to `'gc'`, the `performance.flags`
290 The name of the performance entry.
301 When `performanceEntry.entryType` is equal to `'gc'`, the `performance.kind`
426   performance,
436 performance.mark('test');
440 performance overhead, instances should not be left subscribed to notifications
477   performance,
487   performance.mark(`test${n}`);
492   performance,
502   performance.mark(`test${n}`);
526   performance,
552 performance.mark('test');
553 performance.mark('meow');
572   performance,
606 performance.mark('test');
607 performance.mark('meow');
624   performance,
650 performance.mark('test');
651 performance.mark('meow');
845   performance,
853       performance.mark(`Timeout-${id}-Init`);
860       performance.mark(`Timeout-${id}-Destroy`);
861       performance.measure(`Timeout-${id}`,
871   performance.clearMarks();
888   performance,
895   performance.timerify(mod.Module.prototype.require);
896 require = performance.timerify(require);
913 [Performance Timeline]: https://w3c.github.io/performance-timeline/
920 [`timeOrigin`]: https://w3c.github.io/hr-time/#dom-performance-timeorigin
921 [`window.performance`]: https://developer.mozilla.org/en-US/docs/Web/API/Window/performance