Measuring node main thread occupancy

vscode/src/main.ts

@@ -104,6 +104,7 @@ import { VSCodeSecretStorage, secretStorage } from './services/SecretStorageProv
 import { registerSidebarCommands } from './services/SidebarCommands'
 import { CodyStatusBar } from './services/StatusBar'
 import { createOrUpdateTelemetryRecorderProvider } from './services/telemetry-v2'
+import { ThreadOccupancyMonitor } from './services/thread-occupancy-monitor'
 import {
     enableVerboseDebugMode,
     exportOutputLog,
@@ -123,6 +124,11 @@ export async function start(
 ): Promise<vscode.Disposable> {
     const disposables: vscode.Disposable[] = []
 
+    const threadMonitor = new ThreadOccupancyMonitor()
+    threadMonitor.start()
+
+    disposables.push(new vscode.Disposable(() => threadMonitor.stop()))
+
     //TODO: Add override flag
     const isExtensionModeDevOrTest =
         context.extensionMode === vscode.ExtensionMode.Development ||

vscode/src/services/thread-occupancy-monitor.ts

@@ -0,0 +1,62 @@
+import { telemetryRecorder } from '@sourcegraph/cody-shared'
+
+export class ThreadOccupancyMonitor {
+    private lastMeasurement: number = performance.now()
+    private measurements: number[] = []
+    private measurementInterval: NodeJS.Timeout | null = null
+
+    // Sample interval in ms (e.g. every 1 minute)
+    private readonly SAMPLE_INTERVAL = 60_000
+    // How many samples to keep for rolling average
+    private readonly SAMPLE_WINDOW = 6
+
+    start(): void {
+        if (this.measurementInterval) {
+            return
+        }
+
+        this.measurementInterval = setInterval(() => {
+            this.measure()
+        }, this.SAMPLE_INTERVAL)
+    }
+
+    stop(): void {
+        if (this.measurementInterval) {
+            clearInterval(this.measurementInterval)
+            this.measurementInterval = null
+        }
+    }
+
+    private measure(): void {
+        const now = performance.now()
+        const elapsed = now - this.lastMeasurement
+        this.lastMeasurement = now
+
+        // Get CPU usage for the main thread
+        const cpuUsage = process.cpuUsage()
+        const userCPUMs = cpuUsage.user / 1000 // Convert to ms
+        const systemCPUMs = cpuUsage.system / 1000
+
+        // Calculate occupancy as percentage
+        const occupancy = ((userCPUMs + systemCPUMs) / elapsed) * 100
+
+        // Keep rolling window of measurements
+        this.measurements.push(occupancy)
+        if (this.measurements.length > this.SAMPLE_WINDOW) {
+            this.measurements.shift()
+        }
+
+        this.emitTelemetry(occupancy)
+    }
+
+    private emitTelemetry(occupancy: number): void {
+        telemetryRecorder.recordEvent('cody.performance', 'threadOccupancy', {
+            metadata: {
+                occupancyPercent: Math.round(occupancy),
+                rollingAveragePercent: Math.round(
+                    this.measurements.reduce((a, b) => a + b, 0) / this.measurements.length
+                ),
+            },
+        })
+    }
+}