report on first steady ping

Author: vzaidman

front_end/core/host/RNPerfMetrics.ts

@@ -215,6 +215,12 @@ class RNPerfMetrics {
     }
   }
 
+  firstSteadyPing(): void {
+    this.sendEvent({
+      eventName: 'FirstSteadyPing',
+    });
+  }
+
   heapSnapshotStarted(): void {
     this.sendEvent({
       eventName: 'MemoryPanelActionStarted',
@@ -505,12 +511,16 @@ export type StackTraceFrameUrlResolutionFailed = Readonly<{
   }>,
 }>;
 
+export type FirstSteadyPing = Readonly<{
+  eventName: 'FirstSteadyPing',
+}>;
+
 export type ReactNativeChromeDevToolsEvent =
     EntrypointLoadingStartedEvent|EntrypointLoadingFinishedEvent|DebuggerReadyEvent|BrowserVisibilityChangeEvent|
     BrowserErrorEvent|RemoteDebuggingTerminatedEvent|DeveloperResourceLoadingStartedEvent|
     DeveloperResourceLoadingFinishedEvent|AllInitialDeveloperResourcesLoadingFinished|FuseboxSetClientMetadataStartedEvent|
     FuseboxSetClientMetadataFinishedEvent|MemoryPanelActionStartedEvent|MemoryPanelActionFinishedEvent|
     PanelShownEvent|PanelClosedEvent|StackTraceSymbolicationSucceeded|StackTraceSymbolicationFailed|
-    StackTraceFrameUrlResolutionSucceeded|StackTraceFrameUrlResolutionFailed;
+    StackTraceFrameUrlResolutionSucceeded|StackTraceFrameUrlResolutionFailed|FirstSteadyPing;
 
 export type DecoratedReactNativeChromeDevToolsEvent = CommonEventFields&ReactNativeChromeDevToolsEvent;

front_end/entrypoints/inspector_main/InspectorMain.ts

@@ -15,6 +15,9 @@ import * as UI from '../../ui/legacy/legacy.js';
 
 import nodeIconStyles from './nodeIcon.css.js';
 
+const COOLDOWN_BETWEEN_PINGS = 3000;
+const LOW_PING_THRESHOLD = 200;
+
 const UIStrings = {
   /**
    * @description Text that refers to the main target. The main target is the primary webpage that
@@ -46,6 +49,8 @@ const i18nString = i18n.i18n.getLocalizedString.bind(undefined, str_);
 let inspectorMainImplInstance: InspectorMainImpl;
 
 export class InspectorMainImpl implements Common.Runnable.Runnable {
+  #consecutiveLowPing = 0;
+
   static instance(opts: {
     forceNew: boolean|null,
   } = {forceNew: null}): InspectorMainImpl {
@@ -57,6 +62,28 @@ export class InspectorMainImpl implements Common.Runnable.Runnable {
     return inspectorMainImplInstance;
   }
 
+  async #measureMainConnectionPing(debuggerModel: SDK.DebuggerModel.DebuggerModel): Promise<void> {
+    if (!debuggerModel.debuggerEnabled()) {
+      return;
+    }
+
+    const startMs = Date.now();
+    await debuggerModel.syncDebuggerId();
+    const ping = Date.now() - startMs;
+
+    if (ping > LOW_PING_THRESHOLD) {
+      this.#consecutiveLowPing = 0;
+    } else {
+      this.#consecutiveLowPing++;
+    }
+
+    if (this.#consecutiveLowPing > 1) {
+      Host.rnPerfMetrics.firstSteadyPing();
+    } else {
+      setTimeout(() => void this.#measureMainConnectionPing(debuggerModel), COOLDOWN_BETWEEN_PINGS);
+    }
+  }
+
   async run(): Promise<void> {
     let firstCall = true;
     await SDK.Connections.initMainConnection(async () => {
@@ -94,13 +121,14 @@ export class InspectorMainImpl implements Common.Runnable.Runnable {
       }
       firstCall = false;
 
-      if (waitForDebuggerInPage) {
-        const debuggerModel = target.model(SDK.DebuggerModel.DebuggerModel);
-        if (debuggerModel) {
-          if (!debuggerModel.isReadyToPause()) {
-            await debuggerModel.once(SDK.DebuggerModel.Events.DebuggerIsReadyToPause);
-          }
-          debuggerModel.pause();
+      const debuggerModel = target.model(SDK.DebuggerModel.DebuggerModel);
+      if (debuggerModel) {
+        void this.#measureMainConnectionPing(debuggerModel);
+        if (waitForDebuggerInPage) {
+            if (!debuggerModel.isReadyToPause()) {
+              await debuggerModel.once(SDK.DebuggerModel.Events.DebuggerIsReadyToPause);
+            }
+            debuggerModel.pause();
         }
       }