Bug 1631402 - Remove expired IPC_MAIN_THREAD_LATENCY probes, r=ipc-reviewers,mccr8

Differential Revision: https://phabricator.services.mozilla.com/D135154

ipc/chromium/src/base/pickle.cc

@@ -86,7 +86,7 @@ struct Copier<T, size, true> {
 }  // anonymous namespace
 
 PickleIterator::PickleIterator(const Pickle& pickle)
-    : iter_(pickle.buffers_.Iter()), start_(mozilla::TimeStamp::Now()) {
+    : iter_(pickle.buffers_.Iter()) {
   iter_.Advance(pickle.buffers_, pickle.header_size_);
 }
 
@@ -458,17 +458,6 @@ bool Pickle::WriteSentinel(uint32_t sentinel) { return WriteUInt32(sentinel); }
 void Pickle::EndRead(PickleIterator& iter, uint32_t ipcMsgType) const {
   // FIXME: Deal with the footer somehow...
   // DCHECK(iter.iter_.Done());
-
-  if (NS_IsMainThread() && ipcMsgType != 0) {
-    uint32_t latencyMs =
-        round((mozilla::TimeStamp::Now() - iter.start_).ToMilliseconds());
-    if (latencyMs >= kMinTelemetryIPCReadLatencyMs) {
-      mozilla::Telemetry::Accumulate(
-          mozilla::Telemetry::IPC_READ_MAIN_THREAD_LATENCY_MS,
-          nsDependentCString(IPC::StringFromIPCMessageType(ipcMsgType)),
-          latencyMs);
-    }
-  }
 }
 
 void Pickle::Truncate(PickleIterator* iter) {

ipc/chromium/src/base/pickle.h

@@ -32,7 +32,6 @@ class PickleIterator {
   friend class Pickle;
 
   mozilla::BufferList<InfallibleAllocPolicy>::IterImpl iter_;
-  mozilla::TimeStamp start_;
 
   template <typename T>
   void CopyInto(T* dest);

ipc/chromium/src/chrome/common/ipc_message.cc

@@ -30,7 +30,7 @@ Message::Message()
 }
 
 Message::Message(int32_t routing_id, msgid_t type, uint32_t segment_capacity,
-                 HeaderFlags flags, bool recordWriteLatency)
+                 HeaderFlags flags)
     : UserMessage(&kUserMessageTypeInfo),
       Pickle(sizeof(Header), segment_capacity) {
   MOZ_COUNT_CTOR(IPC::Message);
@@ -46,9 +46,6 @@ Message::Message(int32_t routing_id, msgid_t type, uint32_t segment_capacity,
   header()->num_send_rights = 0;
 #endif
   header()->event_footer_size = 0;
-  if (recordWriteLatency) {
-    create_time_ = mozilla::TimeStamp::Now();
-  }
 }
 
 Message::Message(const char* data, int data_len)
@@ -72,7 +69,7 @@ Message::Message(Message&& other)
 
 /*static*/ Message* Message::IPDLMessage(int32_t routing_id, msgid_t type,
                                          HeaderFlags flags) {
-  return new Message(routing_id, type, 0, flags, true);
+  return new Message(routing_id, type, 0, flags);
 }
 
 /*static*/ Message* Message::ForSyncDispatchError(NestedLevel level) {

ipc/chromium/src/chrome/common/ipc_message.h

@@ -171,12 +171,9 @@ class Message : public mojo::core::ports::UserMessage, public Pickle {
 
   // Initialize a message with a user-defined type, priority value, and
   // destination WebView ID.
-  //
-  // NOTE: `recordWriteLatency` is only passed by IPDL generated message code,
-  // and is used to trigger the IPC_WRITE_LATENCY_MS telemetry.
   Message(int32_t routing_id, msgid_t type,
           uint32_t segmentCapacity = 0,  // 0 for the default capacity.
-          HeaderFlags flags = HeaderFlags(), bool recordWriteLatency = false);
+          HeaderFlags flags = HeaderFlags());
 
   Message(const char* data, int data_len);
 
@@ -252,8 +249,6 @@ class Message : public mojo::core::ports::UserMessage, public Pickle {
 
   const char* name() const { return StringFromIPCMessageType(type()); }
 
-  const mozilla::TimeStamp& create_time() const { return create_time_; }
-
   uint32_t num_handles() const;
 
   bool is_relay() const { return header()->flags.IsRelay(); }
@@ -431,8 +426,6 @@ class Message : public mojo::core::ports::UserMessage, public Pickle {
   // deserializing a message.
   mutable nsTArray<mozilla::UniqueMachSendRight> attached_send_rights_;
 #endif
-
-  mozilla::TimeStamp create_time_;
 };
 
 class MessageInfo {

ipc/glue/MessageChannel.cpp

@@ -135,10 +135,6 @@ namespace ipc {
 
 static const uint32_t kMinTelemetryMessageSize = 4096;
 
-// Note: we round the time we spend to the nearest millisecond. So a min value
-// of 1 ms actually captures from 500us and above.
-static const uint32_t kMinTelemetryIPCWriteLatencyMs = 1;
-
 // Note: we round the time we spend waiting for a response to the nearest
 // millisecond. So a min value of 1 ms actually captures from 500us and above.
 // This is used for both the sending and receiving side telemetry for sync IPC,
@@ -853,20 +849,6 @@ bool MessageChannel::Send(UniquePtr<Message> aMsg) {
     Telemetry::Accumulate(Telemetry::IPC_MESSAGE_SIZE2, aMsg->size());
   }
 
-  // If the message was created by the IPC bindings, the create time will be
-  // recorded. Use this information to report the
-  // IPC_WRITE_MAIN_THREAD_LATENCY_MS (time from message creation to it being
-  // sent).
-  if (NS_IsMainThread() && aMsg->create_time()) {
-    uint32_t latencyMs = round(
-        (mozilla::TimeStamp::Now() - aMsg->create_time()).ToMilliseconds());
-    if (latencyMs >= kMinTelemetryIPCWriteLatencyMs) {
-      mozilla::Telemetry::Accumulate(
-          mozilla::Telemetry::IPC_WRITE_MAIN_THREAD_LATENCY_MS,
-          nsDependentCString(aMsg->name()), latencyMs);
-    }
-  }
-
   MOZ_RELEASE_ASSERT(!aMsg->is_sync());
   MOZ_RELEASE_ASSERT(aMsg->nested_level() != IPC::Message::NESTED_INSIDE_SYNC);
 

ipc/ipdl/ipdl/lower.py

@@ -1943,8 +1943,6 @@ def _generateMessageConstructor(md, segmentSize, protocol, forReply=False):
                         ExprVar(msgid),
                         ExprLiteral.Int(int(segmentSize)),
                         flags,
-                        # Pass `true` to recordWriteLatency to collect telemetry
-                        ExprLiteral.TRUE,
                     ],
                 )
             )

toolkit/components/telemetry/Histograms.json

@@ -15094,30 +15094,6 @@
     "description": "Results of displaying add-on installation notifications.",
     "releaseChannelCollection": "opt-out"
   },
-  "IPC_READ_MAIN_THREAD_LATENCY_MS": {
-    "record_in_processes": ["main", "content", "gpu"],
-    "products": ["firefox", "fennec"],
-    "alert_emails": ["mlayzell@mozilla.com"],
-    "bug_numbers": [1342635],
-    "expires_in_version": "60",
-    "kind": "exponential",
-    "high": 500,
-    "n_buckets": 20,
-    "keyed": true,
-    "description": "Measures the number of milliseconds we spend waiting on the main thread for IPC messages to deserialize their parameters. Note: only messages that take more than 500 microseconds are included in this probe. This probe is keyed on the IPDL message name."
-  },
-  "IPC_WRITE_MAIN_THREAD_LATENCY_MS": {
-    "record_in_processes": ["main", "content", "gpu"],
-    "products": ["firefox", "fennec"],
-    "alert_emails": ["mlayzell@mozilla.com"],
-    "bug_numbers": [1342635],
-    "expires_in_version": "60",
-    "kind": "exponential",
-    "high": 500,
-    "n_buckets": 20,
-    "keyed": true,
-    "description": "Measures the number of milliseconds we spend waiting on the main thread for IPC messages to serialize their parameters. Note: only messages that take more than 500 microseconds are included in this probe. This probe is keyed on the IPDL message name."
-  },
   "INPUT_EVENT_QUEUED_CLICK_MS": {
     "record_in_processes": ["main", "content"],
     "products": ["firefox", "fennec"],