Bug 1505522: Part 2 - Migrate MemoryTelemetry.jsm to C++. r=erahm,chutten

This has benefits both in terms of performance and memory usage. Aside from
the obvious savings of not loading additional JS scripts in every process,
this also allows us to move more of our expensive data collection work to a
background thread, where it doesn't risk janking both parent and content
processes.

MozReview-Commit-ID: 2A593R7bIKB

Differential Revision: https://phabricator.services.mozilla.com/D13872

UltraBlame original commit: bd8001e1f07efc4b6d512bc2c4e49a9dfd91e1db

Author: marco-c

browser/base/content/browser.js

@@ -5582,6 +5582,10 @@ nsBrowserAccess.prototype = {
   canClose() {
     return CanCloseWindow();
   },
+
+  get tabCount() {
+    return gBrowser.tabs.length;
+  },
 };
 
 function onViewToolbarsPopupShowing(aEvent, aInsertPoint) {

browser/base/content/test/performance/browser_startup_content.js

@@ -65,7 +65,6 @@ const whitelist = {
 
 
     "resource://gre/modules/TelemetryController.jsm", 
-    "resource://gre/modules/MemoryTelemetry.jsm", 
     "resource://gre/modules/TelemetryUtils.jsm", 
 
 

dom/interfaces/base/nsIBrowserDOMWindow.idl

@@ -173,5 +173,11 @@ interface nsIBrowserDOMWindow : nsISupports
    * BrowserUtils.jsm for a simple implementation of this method.
    */
   boolean canClose();
+
+  /**
+   * The number browser tabs in the window. This number currently includes
+   * lazy tabs, though for most uses it probably should not.
+   */
+  readonly attribute unsigned long tabCount;
 };
 

dom/ipc/ContentChild.cpp

@@ -17,6 +17,7 @@
 #include "mozilla/Attributes.h"
 #include "mozilla/BackgroundHangMonitor.h"
 #include "mozilla/LookAndFeel.h"
+#include "mozilla/MemoryTelemetry.h"
 #include "mozilla/NullPrincipal.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/ProcessHangMonitorIPC.h"
@@ -3376,6 +3377,12 @@ mozilla::ipc::IPCResult ContentChild::RecvFlushCodeCoverageCounters(
 #endif
 }
 
+mozilla::ipc::IPCResult ContentChild::RecvGetMemoryUniqueSetSize(
+    GetMemoryUniqueSetSizeResolver&& aResolver) {
+  MemoryTelemetry::Get().GetUniqueSetSize(std::move(aResolver));
+  return IPC_OK();
+}
+
 mozilla::ipc::IPCResult ContentChild::RecvSetInputEventQueueEnabled() {
   nsThreadManager::get().EnableMainThreadEventPrioritization();
   return IPC_OK();

dom/ipc/ContentChild.h

@@ -612,6 +612,9 @@ class ContentChild final : public PContentChild,
   virtual mozilla::ipc::IPCResult RecvFlushCodeCoverageCounters(
       FlushCodeCoverageCountersResolver&& aResolver) override;
 
+  virtual mozilla::ipc::IPCResult RecvGetMemoryUniqueSetSize(
+      GetMemoryUniqueSetSizeResolver&& aResolver) override;
+
   virtual mozilla::ipc::IPCResult RecvSetInputEventQueueEnabled() override;
 
   virtual mozilla::ipc::IPCResult RecvFlushInputEventQueue() override;

dom/ipc/PContent.ipdl

@@ -652,6 +652,8 @@ child:
     async ShareCodeCoverageMutex(CrossProcessMutexHandle handle);
     async FlushCodeCoverageCounters() returns (bool unused);
 
+    async GetMemoryUniqueSetSize() returns (int64_t uss);
+
     /*
      * IPC message to enable the input event queue on the main thread of the
      * content process.

toolkit/components/telemetry/app/TelemetryController.jsm

@@ -58,7 +58,6 @@ XPCOMUtils.defineLazyModuleGetters(this, {
   TelemetryEnvironment: "resource://gre/modules/TelemetryEnvironment.jsm",
   TelemetryArchive: "resource://gre/modules/TelemetryArchive.jsm",
   TelemetrySession: "resource://gre/modules/TelemetrySession.jsm",
-  MemoryTelemetry: "resource://gre/modules/MemoryTelemetry.jsm",
   TelemetrySend: "resource://gre/modules/TelemetrySend.jsm",
   TelemetryReportingPolicy: "resource://gre/modules/TelemetryReportingPolicy.jsm",
   TelemetryModules: "resource://gre/modules/ModulesPing.jsm",
@@ -639,7 +638,7 @@ var Impl = {
 
 
     TelemetrySession.earlyInit(this._testMode);
-    MemoryTelemetry.earlyInit(this._testMode);
+    Services.telemetry.earlyInit();
 
 
     TelemetrySend.earlyInit();
@@ -689,7 +688,7 @@ var Impl = {
 
 
         await TelemetrySession.delayedInit();
-        await MemoryTelemetry.delayedInit();
+        await Services.telemetry.delayedInit();
 
         if (Services.prefs.getBoolPref(TelemetryUtils.Preferences.NewProfilePingEnabled, false) &&
             !TelemetrySession.newProfilePingSent) {
@@ -755,7 +754,15 @@ var Impl = {
       this._log.trace("setupContentTelemetry - Content process recording disabled.");
       return;
     }
-    MemoryTelemetry.setupContent(testing);
+    Services.telemetry.earlyInit();
+
+    
+    let delayedTask = new DeferredTask(() => {
+      Services.telemetry.delayedInit();
+    }, testing ? TELEMETRY_TEST_DELAY : TELEMETRY_DELAY,
+       testing ? 0 : undefined);
+
+    delayedTask.arm();
   },
 
 
@@ -788,7 +795,7 @@ var Impl = {
       await TelemetryHealthPing.shutdown();
 
       await TelemetrySession.shutdown();
-      await MemoryTelemetry.shutdown();
+      await Services.telemetry.shutdown();
 
 
       await this._shutdownBarrier.wait();

toolkit/components/telemetry/core/Telemetry.cpp

@@ -33,6 +33,7 @@
 #include "mozilla/Likely.h"
 #include "mozilla/MathAlgorithms.h"
 #include "mozilla/MemoryReporting.h"
+#include "mozilla/MemoryTelemetry.h"
 #include "mozilla/ModuleUtils.h"
 #include "mozilla/Mutex.h"
 #include "mozilla/PoisonIOInterposer.h"
@@ -1736,6 +1737,39 @@ TelemetryImpl::FlushBatchedChildTelemetry() {
   return NS_OK;
 }
 
+NS_IMETHODIMP
+TelemetryImpl::EarlyInit() {
+  Unused << MemoryTelemetry::Get();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TelemetryImpl::DelayedInit() {
+  MemoryTelemetry::Get().DelayedInit();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TelemetryImpl::Shutdown() {
+  MemoryTelemetry::Get().Shutdown();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+TelemetryImpl::GatherMemory(JSContext* aCx, Promise** aResult) {
+  ErrorResult rv;
+  RefPtr<Promise> promise = Promise::Create(xpc::CurrentNativeGlobal(aCx), rv);
+  if (rv.Failed()) {
+    return rv.StealNSResult();
+  }
+
+  MemoryTelemetry::Get().GatherReports(
+      [promise]() { promise->MaybeResolve(JS::UndefinedHandleValue); });
+
+  promise.forget(aResult);
+  return NS_OK;
+}
+
 }  
 
 

toolkit/components/telemetry/core/nsITelemetry.idl

@@ -603,4 +603,33 @@ interface nsITelemetry : nsISupports
    * Please note that this is only intended to be used by GeckoViewTelemetryController.
    */
   void clearProbes();
+
+  /**
+   * Does early, cheap initialization for native telemetry data providers.
+   * Currently, this includes only MemoryTelemetry.
+   */
+  void earlyInit();
+
+  /**
+   * Does late, expensive initialization for native telemetry data providers.
+   * Currently, this includes only MemoryTelemetry.
+   *
+   * This should only be called after startup has completed and the event loop
+   * is idle.
+   */
+  void delayedInit();
+
+  /**
+   * Shuts down native telemetry providers. Currently, this includes only
+   * MemoryTelemetry.
+   */
+  void shutdown();
+
+  /**
+   * Gathers telemetry data for memory usage and records it to the data store.
+   * Returns a promise which resolves when asynchronous data collection has
+   * completed and all data has been recorded.
+   */
+  [implicit_jscontext]
+  Promise gatherMemory();
 };

toolkit/components/telemetry/moz.build

@@ -45,6 +45,7 @@ BROWSER_CHROME_MANIFESTS += ['tests/browser/browser.ini']
 
 XPIDL_SOURCES += [
     'core/nsITelemetry.idl',
+    'other/GCTelemetry.idl',
 ]
 
 XPIDL_MODULE = 'telemetry'
@@ -107,7 +108,6 @@ EXTRA_JS_MODULES += [
     'app/TelemetryTimestamps.jsm',
     'app/TelemetryUtils.jsm',
     'other/GCTelemetry.jsm',
-    'other/MemoryTelemetry.jsm',
     'other/UITelemetry.jsm',
     'pings/CoveragePing.jsm',
     'pings/EventPing.jsm',

toolkit/components/telemetry/other/GCTelemetry.idl

@@ -0,0 +1,18 @@
+/* -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 8 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+[scriptable, uuid(6ab1c3c1-31cf-4a32-8484-97b5ef0627af)]
+interface mozIGCTelemetry : nsISupports {
+  void init();
+
+  void shutdown();
+};
+
+[scriptable, uuid(93b2a0ca-6306-41c1-b296-c57cad5175c7)]
+interface mozIGCTelemetryJSM : nsISupports {
+  readonly attribute mozIGCTelemetry GCTelemetry;
+};