Improve stats collection for plugins in the background

Summary:
This diff improves two things:
1. Stats are now gathered on every `trackUsage` tick, rather than only when there is a selection
2. The stats now include a delta to compare it with the previous tick

Reviewed By: passy

Differential Revision: D19514231

fbshipit-source-id: 1854c1dc03c63a03db8c7040c185d2629e1b9ea2

src/dispatcher/tracking.tsx

@@ -13,7 +13,10 @@ import {performance} from 'perf_hooks';
 import {Store} from '../reducers/index';
 import {Logger} from '../fb-interfaces/Logger';
 import Client from '../Client';
-import {getPluginBackgroundStats} from '../utils/messageQueue';
+import {
+  getPluginBackgroundStats,
+  resetPluginBackgroundStatsDelta,
+} from '../utils/messageQueue';
 import {
   clearTimeline,
   TrackingEvent,
@@ -90,6 +93,9 @@ export default (store: Store, logger: Logger) => {
         }),
     );
 
+    logger.track('usage', 'plugin-stats', getPluginBackgroundStats());
+    resetPluginBackgroundStatsDelta();
+
     if (
       !state.application.windowIsFocused ||
       !selectedDevice ||
@@ -115,7 +121,6 @@ export default (store: Store, logger: Logger) => {
       os: selectedDevice.os,
       device: selectedDevice.title,
       plugin: selectedPlugin,
-      pluginStats: getPluginBackgroundStats(),
       app,
       sdkVersion,
       isForeground: state.application.windowIsFocused,

src/utils/messageQueue.tsx

@@ -22,13 +22,22 @@ import {pluginIsStarred, getSelectedPluginKey} from '../reducers/connections';
 const MAX_BACKGROUND_TASK_TIME = 25;
 
 type StatEntry = {
-  cpuTime: number; // Total time spend in persisted Reducer
-  messages: number; // amount of message received for this plugin
+  cpuTimeTotal: number; // Total time spend in persisted Reducer
+  cpuTimeDelta: number; // Time spend since previous tracking tick
+  messageCountTotal: number; // amount of message received for this plugin
+  messageCountDelta: number; // amout of messages received since previous tracking tick
   maxTime: number; // maximum time spend in a single reducer call
 };
 
 const pluginBackgroundStats = new Map<string, StatEntry>();
 
+export function resetPluginBackgroundStatsDelta() {
+  pluginBackgroundStats.forEach(stat => {
+    stat.cpuTimeDelta = 0;
+    stat.messageCountDelta = 0;
+  });
+}
+
 export function getPluginBackgroundStats(): {[plugin: string]: StatEntry} {
   return Array.from(Object.entries(pluginBackgroundStats)).reduce(
     (aggregated, [pluginName, data]) => {
@@ -44,10 +53,21 @@ if (window) {
   window.flipperPrintPluginBackgroundStats = () => {
     console.table(
       Array.from(pluginBackgroundStats.entries()).map(
-        ([plugin, {cpuTime, messages, maxTime}]) => ({
+        ([
           plugin,
-          cpuTime,
-          messages,
+          {
+            cpuTimeDelta,
+            cpuTimeTotal,
+            messageCountDelta,
+            messageCountTotal,
+            maxTime,
+          },
+        ]) => ({
+          plugin,
+          cpuTimeTotal,
+          messageCountTotal,
+          cpuTimeDelta,
+          messageCountDelta,
           maxTime,
         }),
       ),
@@ -57,11 +77,19 @@ if (window) {
 
 function addBackgroundStat(plugin: string, cpuTime: number) {
   if (!pluginBackgroundStats.has(plugin)) {
-    pluginBackgroundStats.set(plugin, {cpuTime: 0, messages: 0, maxTime: 0});
+    pluginBackgroundStats.set(plugin, {
+      cpuTimeDelta: 0,
+      cpuTimeTotal: 0,
+      messageCountDelta: 0,
+      messageCountTotal: 0,
+      maxTime: 0,
+    });
   }
   const stat = pluginBackgroundStats.get(plugin)!;
-  stat.cpuTime += cpuTime;
-  stat.messages += 1;
+  stat.cpuTimeDelta += cpuTime;
+  stat.cpuTimeTotal += cpuTime;
+  stat.messageCountDelta += 1;
+  stat.messageCountTotal += 1;
   stat.maxTime = Math.max(stat.maxTime, cpuTime);
   if (cpuTime > MAX_BACKGROUND_TASK_TIME) {
     console.warn(