Fine-grained Garbage Collection Monitoring

Snippet

Fine-grained Garbage Collection Monitoring

Using PerformanceObserver with the 'gc' entry type allows applications to monitor memory management behavior in real-time. This is crucial for detecting memory pressure or 'stop-the-world' pauses that could impact latency in high-performance servers.

snippet.js
javascript
import { PerformanceObserver } from 'node:perf_hooks';
 
const obs = new PerformanceObserver((list) => {
  const entry = list.getEntries()[0];
  console.log(`GC detected: ${entry.kind} | Duration: ${entry.duration}ms`);
  console.log(`Heap used: ${entry.detail.afterUsedHeapSize}`);
});
 
obs.observe({ entryTypes: ['gc'] });

nodejs

Breakdown

import { PerformanceObserver } from 'node:perf_hooks';

Accesses Node's performance measurement utility.

const entry = list.getEntries()[0];

Retrieves the specific GC performance entry containing duration and type.

entry.kind

Indicates the type of GC (e.g., 'scavenge' for minor or 'mark-sweep-compact' for major).

obs.observe({ entryTypes: ['gc'] });

Starts listening specifically for Garbage Collection events from the V8 engine.

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Fine-grained Garbage Collection Monitoring

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