Bug 1260908 - Record IPC message sizes (r=dvander)

dom/base/nsFrameMessageManager.cpp

@@ -69,6 +69,8 @@ using namespace mozilla;
 using namespace mozilla::dom;
 using namespace mozilla::dom::ipc;
 
+static const int kMinTelemetryMessageSize = 8192;
+
 nsFrameMessageManager::nsFrameMessageManager(mozilla::dom::ipc::MessageManagerCallback* aCallback,
                                              nsFrameMessageManager* aParentManager,
                                              /* mozilla::dom::ipc::MessageManagerFlags */ uint32_t aFlags)
@@ -730,6 +732,12 @@ nsFrameMessageManager::SendMessage(const nsAString& aMessageName,
     return NS_ERROR_DOM_DATA_CLONE_ERR;
   }
 
+  if (data.DataLength() >= kMinTelemetryMessageSize) {
+    Telemetry::Accumulate(Telemetry::MESSAGE_MANAGER_MESSAGE_SIZE,
+                          NS_ConvertUTF16toUTF8(aMessageName),
+                          data.DataLength());
+  }
+
   JS::Rooted<JSObject*> objects(aCx);
   if (aArgc >= 3 && aObjects.isObject()) {
     objects = &aObjects.toObject();
@@ -810,6 +818,12 @@ nsFrameMessageManager::DispatchAsyncMessage(const nsAString& aMessageName,
     return NS_ERROR_DOM_DATA_CLONE_ERR;
   }
 
+  if (data.DataLength() >= kMinTelemetryMessageSize) {
+    Telemetry::Accumulate(Telemetry::MESSAGE_MANAGER_MESSAGE_SIZE,
+                          NS_ConvertUTF16toUTF8(aMessageName),
+                          data.DataLength());
+  }
+
   JS::Rooted<JSObject*> objects(aCx);
   if (aArgc >= 3 && aObjects.isObject()) {
     objects = &aObjects.toObject();

ipc/glue/MessageChannel.cpp

@@ -118,6 +118,8 @@ static MessageChannel* gParentProcessBlocker;
 namespace mozilla {
 namespace ipc {
 
+static const int kMinTelemetryMessageSize = 8192;
+
 const int32_t MessageChannel::kNoTimeout = INT32_MIN;
 
 // static
@@ -749,6 +751,10 @@ MessageChannel::Echo(Message* aMsg)
 bool
 MessageChannel::Send(Message* aMsg)
 {
+    if (aMsg->size() >= kMinTelemetryMessageSize) {
+        Telemetry::Accumulate(Telemetry::IPC_MESSAGE_SIZE, nsCString(aMsg->name()), aMsg->size());
+    }
+
     CxxStackFrame frame(*this, OUT_MESSAGE, aMsg);
 
     nsAutoPtr<Message> msg(aMsg);
@@ -1045,6 +1051,10 @@ MessageChannel::ProcessPendingRequests(AutoEnterTransaction& aTransaction)
 bool
 MessageChannel::Send(Message* aMsg, Message* aReply)
 {
+    if (aMsg->size() >= kMinTelemetryMessageSize) {
+        Telemetry::Accumulate(Telemetry::IPC_MESSAGE_SIZE, nsCString(aMsg->name()), aMsg->size());
+    }
+
     nsAutoPtr<Message> msg(aMsg);
 
     // Sanity checks.

toolkit/components/telemetry/Histograms.json

@@ -10495,5 +10495,25 @@
     "kind": "count",
     "bug_numbers": [1237198],
     "description": "Count tiny plugin content"
+  },
+  "IPC_MESSAGE_SIZE": {
+    "alert_emails": ["wmccloskey@mozilla.com"],
+    "bug_numbers": [1260908],
+    "expires_in_version": "55",
+    "kind": "exponential",
+    "high": 8000000,
+    "n_buckets": 50,
+    "keyed": true,
+    "description": "Measures the size of IPC messages by message name"
+  },
+  "MESSAGE_MANAGER_MESSAGE_SIZE": {
+    "alert_emails": ["wmccloskey@mozilla.com"],
+    "bug_numbers": [1260908],
+    "expires_in_version": "55",
+    "kind": "exponential",
+    "high": 8000000,
+    "n_buckets": 50,
+    "keyed": true,
+    "description": "Measures the size of message manager messages by message name"
   }
 }