Introduce FuseboxTracer for DevTools tracing (facebook#44840)

Summary:
Pull Request resolved: facebook#44840

Changelog: [Internal]

Introduce a simplified and minimal tracing backend for Fusebox. This backend is sufficient to implement a pretty usable performance panel.

Although the more I see how easy this is and how annoying working with Perfetto is, the more I think we should just maintain this going forward. Anyways we can figure that out incrementally. For now the plan is still for this to be temporary.

Reviewed By: motiz88

Differential Revision: D57981944

fbshipit-source-id: b3d8c6e8c5a18311bbe98254f8ddf3810fa1334b

Author: Benoit Girard

packages/react-native/ReactCommon/jsinspector-modern/CMakeLists.txt

@@ -23,4 +23,5 @@ target_link_libraries(jsinspector
         glog
         react_featureflags
         runtimeexecutor
+        reactperflogger
 )

packages/react-native/ReactCommon/jsinspector-modern/HostAgent.cpp

@@ -15,6 +15,8 @@
 
 #include <chrono>
 
+#include <reactperflogger/fusebox/FuseboxTracer.h>
+
 using namespace std::chrono;
 using namespace std::literals::string_view_literals;
 
@@ -146,25 +148,41 @@ void HostAgent::handleRequest(const cdp::PreparsedRequest& req) {
     shouldSendOKResponse = true;
     isFinishedHandlingRequest = true;
   } else if (req.method == "Tracing.start") {
-    // @cdp Tracing.start is implemented as a stub only.
-    frontendChannel_(cdp::jsonNotification(
-        // @cdp Tracing.bufferUsage is implemented as a stub only.
-        "Tracing.bufferUsage",
-        folly::dynamic::object("percentFull", 0)("eventCount", 0)("value", 0)));
-    shouldSendOKResponse = true;
+    // @cdp Tracing.start support is experimental.
+    if (FuseboxTracer::getFuseboxTracer().startTracing()) {
+      shouldSendOKResponse = true;
+    } else {
+      frontendChannel_(cdp::jsonError(
+          req.id,
+          cdp::ErrorCode::InternalError,
+          "Tracing session already started"));
+      return;
+    }
     isFinishedHandlingRequest = true;
   } else if (req.method == "Tracing.end") {
-    // @cdp Tracing.end is implemented as a stub only.
-    frontendChannel_(cdp::jsonNotification(
-        // @cdp Tracing.dataCollected is implemented as a stub only.
-        "Tracing.dataCollected",
-        folly::dynamic::object("value", folly::dynamic::array())));
+    // @cdp Tracing.end support is experimental.
+    bool firstChunk = true;
+    auto id = req.id;
+    bool wasStopped = FuseboxTracer::getFuseboxTracer().stopTracing(
+        [this, firstChunk, id](const folly::dynamic& eventsChunk) {
+          if (firstChunk) {
+            frontendChannel_(cdp::jsonResult(id));
+          }
+          frontendChannel_(cdp::jsonNotification(
+              "Tracing.dataCollected",
+              folly::dynamic::object("value", eventsChunk)));
+        });
+    if (!wasStopped) {
+      frontendChannel_(cdp::jsonError(
+          req.id,
+          cdp::ErrorCode::InternalError,
+          "Tracing session not started"));
+      return;
+    }
     frontendChannel_(cdp::jsonNotification(
-        // @cdp Tracing.tracingComplete is implemented as a stub only.
         "Tracing.tracingComplete",
         folly::dynamic::object("dataLossOccurred", false)));
-    shouldSendOKResponse = true;
-    isFinishedHandlingRequest = true;
+    return;
   }
 
   if (!isFinishedHandlingRequest && instanceAgent_ &&

packages/react-native/ReactCommon/jsinspector-modern/React-jsinspector.podspec

@@ -54,6 +54,7 @@ Pod::Spec.new do |s|
   s.dependency "DoubleConversion"
   s.dependency "React-runtimeexecutor", version
   s.dependency "React-jsi"
+  s.dependency "React-perflogger", version
   if ENV["USE_HERMES"] == nil || ENV["USE_HERMES"] == "1"
     s.dependency "hermes-engine"
   end

packages/react-native/ReactCommon/react/nativemodule/webperformance/NativePerformance.cpp

@@ -15,7 +15,8 @@
 #include <cxxreact/ReactMarker.h>
 #include <jsi/instrumentation.h>
 #include <react/performance/timeline/PerformanceEntryReporter.h>
-
+#include <reactperflogger/fusebox/FuseboxTracer.h>
+#include "NativePerformance.h"
 #include "Plugins.h"
 
 #ifdef WITH_PERFETTO
@@ -112,6 +113,17 @@ void NativePerformance::measure(
     }
   }
 #endif
+  std::string trackName = "Web Performance";
+  const int TRACK_PREFIX = 6;
+  if (name.starts_with("Track:")) {
+    const auto trackNameDelimiter = name.find(':', TRACK_PREFIX);
+    if (trackNameDelimiter != std::string::npos) {
+      trackName = name.substr(TRACK_PREFIX, trackNameDelimiter - TRACK_PREFIX);
+      name = name.substr(trackNameDelimiter + 1);
+    }
+  }
+  FuseboxTracer::getFuseboxTracer().addEvent(
+      name, (uint64_t)startTime, (uint64_t)endTime, trackName);
   PerformanceEntryReporter::getInstance()->measure(
       name, startTime, endTime, duration, startMark, endMark);
 }

packages/react-native/ReactCommon/reactperflogger/CMakeLists.txt

@@ -13,7 +13,12 @@ add_compile_options(
         -Wall
         -Wpedantic)
 
-file(GLOB reactperflogger_SRC CONFIGURE_DEPENDS reactperflogger/*.cpp)
+
+file(GLOB reactperflogger_SRC CONFIGURE_DEPENDS
+        reactperflogger/*.cpp
+        fusebox/*.cpp)
 add_library(reactperflogger STATIC ${reactperflogger_SRC})
 
 target_include_directories(reactperflogger PUBLIC .)
+
+target_link_libraries(reactperflogger folly_runtime)

packages/react-native/ReactCommon/reactperflogger/React-perflogger.podspec

@@ -19,7 +19,13 @@ end
 folly_config = get_folly_config()
 folly_compiler_flags = folly_config[:compiler_flags]
 folly_version = folly_config[:version]
-boost_compiler_flags = '-Wno-documentation'
+
+header_search_paths = [
+  "\"$(PODS_TARGET_SRCROOT)/..\"",
+  "\"$(PODS_ROOT)/RCT-Folly\"",
+  "\"$(PODS_ROOT)/DoubleConversion\"",
+  "\"$(PODS_ROOT)/fmt/include\""
+]
 
 Pod::Spec.new do |s|
   s.name                   = "React-perflogger"
@@ -30,7 +36,15 @@ Pod::Spec.new do |s|
   s.author                 = "Meta Platforms, Inc. and its affiliates"
   s.platforms              = min_supported_versions
   s.source                 = source
-  s.source_files           = "**/*.{cpp,h}"
+  s.source_files           = "reactperflogger/*.{cpp,h}", "fusebox/*.{cpp,h}"
   s.header_dir             = "reactperflogger"
   s.pod_target_xcconfig    = { "CLANG_CXX_LANGUAGE_STANDARD" => "c++20" }
+  s.compiler_flags         = folly_compiler_flags
+  s.pod_target_xcconfig    = {
+    "CLANG_CXX_LANGUAGE_STANDARD" => "c++20",
+    "HEADER_SEARCH_PATHS" => header_search_paths.join(' '),
+  }
+
+  s.dependency "RCT-Folly", folly_version
+  s.dependency "DoubleConversion"
 end

packages/react-native/ReactCommon/reactperflogger/fusebox/FuseboxTracer.cpp

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <mutex>
+#include <unordered_map>
+
+#include "FuseboxTracer.h"
+
+namespace facebook::react {
+
+bool FuseboxTracer::isTracing() {
+  std::lock_guard lock(mutex_);
+  return tracing_;
+}
+
+bool FuseboxTracer::startTracing() {
+  std::lock_guard lock(mutex_);
+  if (tracing_) {
+    return false;
+  }
+  tracing_ = true;
+  return true;
+}
+
+bool FuseboxTracer::stopTracing(
+    const std::function<void(const folly::dynamic& eventsChunk)>&
+        resultCallback) {
+  std::lock_guard lock(mutex_);
+
+  if (!tracing_) {
+    return false;
+  }
+
+  tracing_ = false;
+  if (buffer_.empty()) {
+    return true;
+  }
+
+  auto traceEvents = folly::dynamic::array();
+  auto savedBuffer = std::move(buffer_);
+  buffer_.clear();
+
+  std::unordered_map<std::string, uint64_t> trackIdMap;
+  uint64_t nextTrack = 1000;
+
+  // Name the main process. Only one process is supported currently.
+  traceEvents.push_back(folly::dynamic::object(
+      "args", folly::dynamic::object("name", "Main App"))("cat", "__metadata")(
+      "name", "process_name")("ph", "M")("pid", 1000)("tid", 0)("ts", 0));
+
+  for (auto& event : savedBuffer) {
+    if (!trackIdMap.contains(event.track)) {
+      auto trackId = nextTrack++;
+      trackIdMap[event.track] = trackId;
+      // New track
+      traceEvents.push_back(folly::dynamic::object(
+          "args", folly::dynamic::object("name", event.track))(
+          "cat", "__metadata")("name", "thread_name")("ph", "M")("pid", 1000)(
+          "tid", trackId)("ts", 0));
+    }
+    auto trackId = trackIdMap[event.track];
+
+    // New event
+    traceEvents.push_back(folly::dynamic::object(
+        "args", folly::dynamic::object())("cat", "react.native")(
+        "dur", (event.end - event.start) * 1000)("name", event.name)("ph", "X")(
+        "ts", event.start * 1000)("pid", 1000)("tid", trackId));
+
+    if (traceEvents.size() >= 1000) {
+      resultCallback(traceEvents);
+      traceEvents = folly::dynamic::array();
+    }
+  }
+
+  if (traceEvents.size() >= 1) {
+    resultCallback(traceEvents);
+  }
+  return true;
+}
+
+void FuseboxTracer::addEvent(
+    const std::string& name,
+    uint64_t start,
+    uint64_t end,
+    const std::string& track) {
+  std::lock_guard<std::mutex> lock(mutex_);
+  if (!tracing_) {
+    return;
+  }
+  buffer_.push_back(BufferEvent{start, end, name, track});
+}
+
+/* static */ FuseboxTracer& FuseboxTracer::getFuseboxTracer() {
+  static FuseboxTracer tracer;
+  return tracer;
+}
+
+} // namespace facebook::react

packages/react-native/ReactCommon/reactperflogger/fusebox/FuseboxTracer.h

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <functional>
+#include <vector>
+#include "folly/dynamic.h"
+
+namespace facebook::react {
+
+struct BufferEvent {
+  uint64_t start;
+  uint64_t end;
+  std::string name;
+  std::string track;
+};
+
+class FuseboxTracer {
+ public:
+  FuseboxTracer(const FuseboxTracer&) = delete;
+
+  bool isTracing();
+  // Verifies that tracing isn't started and starts tracing all in one step.
+  // Returns true if we were able to successful start tracing.
+  bool startTracing();
+  // Verifies that we're tracing and dumps the trace all in one step to avoid
+  // TOCTOU bugs. Returns false if we're not tracing. No result callbacks
+  // are expected in that scenario.
+  bool stopTracing(const std::function<void(const folly::dynamic& eventsChunk)>&
+                       resultCallback);
+  void addEvent(
+      const std::string& name,
+      uint64_t start,
+      uint64_t end,
+      const std::string& track);
+
+  static FuseboxTracer& getFuseboxTracer();
+
+ private:
+  FuseboxTracer() {}
+
+  bool tracing_{false};
+  std::vector<BufferEvent> buffer_;
+  std::mutex mutex_;
+};
+
+} // namespace facebook::react

packages/react-native/ReactCommon/reactperflogger/fusebox/tests/FuseboxTracerTest.cpp

@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <gtest/gtest.h>
+
+#include <reactperflogger/fusebox/FuseboxTracer.h>
+
+using namespace ::testing;
+
+namespace facebook::react {
+
+namespace {
+
+class FuseboxTracerTest : public ::testing::Test {
+ protected:
+  FuseboxTracerTest() = default;
+
+  ~FuseboxTracerTest() override = default;
+
+  void SetUp() override {
+    stopTracingAndCollect();
+  }
+
+  void TearDown() override {
+    stopTracingAndCollect();
+  }
+
+  folly::dynamic stopTracingAndCollect() {
+    folly::dynamic trace = folly::dynamic::array;
+    FuseboxTracer::getFuseboxTracer().stopTracing(
+        [&trace](const folly::dynamic& eventsChunk) {
+          for (const auto& event : eventsChunk) {
+            trace.push_back(event);
+          }
+        });
+    return trace;
+  }
+};
+
+} // namespace
+
+TEST_F(FuseboxTracerTest, TracingOffByDefault) {
+  EXPECT_FALSE(FuseboxTracer::getFuseboxTracer().isTracing());
+}
+
+TEST_F(FuseboxTracerTest, TracingOn) {
+  FuseboxTracer::getFuseboxTracer().startTracing();
+  EXPECT_TRUE(FuseboxTracer::getFuseboxTracer().isTracing());
+  stopTracingAndCollect();
+}
+
+TEST_F(FuseboxTracerTest, DiscardEventWhenNotOn) {
+  EXPECT_FALSE(FuseboxTracer::getFuseboxTracer().isTracing());
+  EXPECT_EQ(stopTracingAndCollect().size(), 0);
+  FuseboxTracer::getFuseboxTracer().addEvent("test", 0, 0, "default track");
+  FuseboxTracer::getFuseboxTracer().addEvent("test", 0, 0, "default track");
+  EXPECT_EQ(stopTracingAndCollect().size(), 0);
+}
+
+TEST_F(FuseboxTracerTest, NoDefaultEvents) {
+  FuseboxTracer::getFuseboxTracer().startTracing();
+  EXPECT_EQ(stopTracingAndCollect().size(), 0);
+}
+
+TEST_F(FuseboxTracerTest, SimpleEvent) {
+  FuseboxTracer::getFuseboxTracer().startTracing();
+  FuseboxTracer::getFuseboxTracer().addEvent("test", 0, 0, "default track");
+  EXPECT_GE(stopTracingAndCollect().size(), 1);
+}
+
+TEST_F(FuseboxTracerTest, MultiEvents) {
+  FuseboxTracer::getFuseboxTracer().startTracing();
+  for (int i = 0; i < 10; i++) {
+    FuseboxTracer::getFuseboxTracer().addEvent("test", 0, 0, "default track");
+  }
+  EXPECT_GE(stopTracingAndCollect().size(), 10);
+  EXPECT_EQ(stopTracingAndCollect().size(), 0);
+}
+
+TEST_F(FuseboxTracerTest, ShouldEndTracingEvenIfThereIsNoEvents) {
+  FuseboxTracer::getFuseboxTracer().startTracing();
+  EXPECT_EQ(stopTracingAndCollect().size(), 0);
+  EXPECT_FALSE(FuseboxTracer::getFuseboxTracer().isTracing());
+}
+
+} // namespace facebook::react