Add Systrace instrumentation to RuntimeScheduler (#37880)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/37880

This adds systrace sections for the most relevant parts of `RuntimeScheduler`. This helps us identify how things are scheduled, which in this case makes it obvious we're not dispatching events the most efficient way (as top-level callbacks in the runtime executor instead of as tasks in the scheduler).

Changelog: [internal]

Reviewed By: rshest

Differential Revision: D46556399

fbshipit-source-id: 93a13a2c5ec18a34712546889de21792671d5d2c

packages/react-native/ReactCommon/react/renderer/runtimescheduler/CMakeLists.txt

@@ -25,4 +25,5 @@ target_link_libraries(react_render_runtimescheduler
         jsi
         react_debug
         react_render_core
+        react_render_debug
         runtimeexecutor)

packages/react-native/ReactCommon/react/renderer/runtimescheduler/React-runtimescheduler.podspec

@@ -55,6 +55,7 @@ Pod::Spec.new do |s|
   s.dependency "React-runtimeexecutor"
   s.dependency "React-callinvoker"
   s.dependency "React-debug"
+  s.dependency "React-rendererdebug"
   s.dependency "React-utils"
   s.dependency "glog"
   s.dependency "RCT-Folly", folly_version

packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler.cpp

@@ -8,6 +8,7 @@
 #include "RuntimeScheduler.h"
 #include "SchedulerPriorityUtils.h"
 
+#include <react/renderer/debug/SystraceSection.h>
 #include <utility>
 #include "ErrorUtils.h"
 
@@ -21,10 +22,13 @@ RuntimeScheduler::RuntimeScheduler(
     : runtimeExecutor_(std::move(runtimeExecutor)), now_(std::move(now)) {}
 
 void RuntimeScheduler::scheduleWork(RawCallback callback) const {
+  SystraceSection s("RuntimeScheduler::scheduleWork");
+
   runtimeAccessRequests_ += 1;
 
   runtimeExecutor_(
       [this, callback = std::move(callback)](jsi::Runtime& runtime) {
+        SystraceSection s2("RuntimeScheduler::scheduleWork callback");
         runtimeAccessRequests_ -= 1;
         callback(runtime);
         startWorkLoop(runtime);
@@ -78,10 +82,15 @@ RuntimeSchedulerTimePoint RuntimeScheduler::now() const noexcept {
 }
 
 void RuntimeScheduler::executeNowOnTheSameThread(RawCallback callback) {
+  SystraceSection s("RuntimeScheduler::executeNowOnTheSameThread");
+
   runtimeAccessRequests_ += 1;
   executeSynchronouslyOnSameThread_CAN_DEADLOCK(
       runtimeExecutor_,
       [this, callback = std::move(callback)](jsi::Runtime& runtime) {
+        SystraceSection s2(
+            "RuntimeScheduler::executeNowOnTheSameThread callback");
+
         runtimeAccessRequests_ -= 1;
         isSynchronous_ = true;
         callback(runtime);
@@ -95,6 +104,8 @@ void RuntimeScheduler::executeNowOnTheSameThread(RawCallback callback) {
 }
 
 void RuntimeScheduler::callExpiredTasks(jsi::Runtime& runtime) {
+  SystraceSection s("RuntimeScheduler::callExpiredTasks");
+
   auto previousPriority = currentPriority_;
   try {
     while (!taskQueue_.empty()) {
@@ -128,6 +139,8 @@ void RuntimeScheduler::scheduleWorkLoopIfNecessary() const {
 }
 
 void RuntimeScheduler::startWorkLoop(jsi::Runtime& runtime) const {
+  SystraceSection s("RuntimeScheduler::startWorkLoop");
+
   auto previousPriority = currentPriority_;
   isPerformingWork_ = true;
   try {
@@ -155,6 +168,13 @@ void RuntimeScheduler::executeTask(
     jsi::Runtime& runtime,
     std::shared_ptr<Task> task,
     bool didUserCallbackTimeout) const {
+  SystraceSection s(
+      "RuntimeScheduler::executeTask",
+      "priority",
+      serialize(task->priority),
+      "didUserCallbackTimeout",
+      didUserCallbackTimeout);
+
   currentPriority_ = task->priority;
   auto result = task->execute(runtime, didUserCallbackTimeout);