Report JavaScript thread (facebook#49395)

Summary: Pull Request resolved: facebook#49395 # Changelog: [Internal] Adding a new method to `RuntimeTarget` that will register it for Tracing. In our case, it will schedule a callback on JS executor that will register JavaScript thread with `PerformanceTracer`. Reviewed By: huntie Differential Revision: D69530984
hoxyq · Feb 27, 2025 · 13fc4d2 · 13fc4d2
1 parent 71a7842
commit 13fc4d2
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Showing 8 changed files with 45 additions and 2 deletions.
diff --git a/packages/react-native/ReactCommon/jsinspector-modern/InstanceAgent.cpp b/packages/react-native/ReactCommon/jsinspector-modern/InstanceAgent.cpp
@@ -154,6 +154,7 @@ void InstanceAgent::maybeSendPendingConsoleMessages() {
 
 void InstanceAgent::startTracing() {
   if (runtimeAgent_) {
+    runtimeAgent_->registerForTracing();
     runtimeAgent_->enableSamplingProfiler();
   }
 }

diff --git a/packages/react-native/ReactCommon/jsinspector-modern/InstanceAgent.h b/packages/react-native/ReactCommon/jsinspector-modern/InstanceAgent.h
@@ -12,15 +12,14 @@
 #include "SessionState.h"
 
 #include <jsinspector-modern/InspectorInterfaces.h>
+#include <jsinspector-modern/InstanceTarget.h>
 #include <jsinspector-modern/RuntimeAgent.h>
 #include <jsinspector-modern/tracing/InstanceTracingProfile.h>
 
 #include <functional>
 
 namespace facebook::react::jsinspector_modern {
 
-class InstanceTarget;
-
 /**
  * An Agent that handles requests from the Chrome DevTools Protocol for the
  * given InstanceTarget.

diff --git a/packages/react-native/ReactCommon/jsinspector-modern/RuntimeAgent.cpp b/packages/react-native/ReactCommon/jsinspector-modern/RuntimeAgent.cpp
@@ -149,6 +149,10 @@ RuntimeAgent::~RuntimeAgent() {
   sessionState_.lastRuntimeAgentExportedState = getExportedState();
 }
 
+void RuntimeAgent::registerForTracing() {
+  targetController_.registerForTracing();
+}
+
 void RuntimeAgent::enableSamplingProfiler() {
   targetController_.enableSamplingProfiler();
 }

diff --git a/packages/react-native/ReactCommon/jsinspector-modern/RuntimeAgent.h b/packages/react-native/ReactCommon/jsinspector-modern/RuntimeAgent.h
@@ -83,6 +83,12 @@ class RuntimeAgent final {
    */
   ExportedState getExportedState();
 
+  /**
+   * Registers the corresponding RuntimeTarget for Tracing: might enable some
+   * capabilities that will be later used in Tracing Profile.
+   */
+  void registerForTracing();
+
   /**
    * Start sampling profiler for the corresponding RuntimeTarget.
    */

diff --git a/packages/react-native/ReactCommon/jsinspector-modern/RuntimeTarget.cpp b/packages/react-native/ReactCommon/jsinspector-modern/RuntimeTarget.cpp
@@ -8,6 +8,7 @@
 #include "SessionState.h"
 
 #include <jsinspector-modern/RuntimeTarget.h>
+#include <jsinspector-modern/tracing/PerformanceTracer.h>
 
 using namespace facebook::jsi;
 
@@ -159,6 +160,10 @@ void RuntimeTargetController::notifyDebuggerSessionDestroyed() {
   target_.emitDebuggerSessionDestroyed();
 }
 
+void RuntimeTargetController::registerForTracing() {
+  target_.registerForTracing();
+}
+
 void RuntimeTargetController::enableSamplingProfiler() {
   target_.enableSamplingProfiler();
 }
@@ -172,6 +177,12 @@ RuntimeTargetController::collectSamplingProfile() {
   return target_.collectSamplingProfile();
 }
 
+void RuntimeTarget::registerForTracing() {
+  jsExecutor_([](auto& /*runtime*/) {
+    PerformanceTracer::getInstance().reportJavaScriptThread();
+  });
+}
+
 void RuntimeTarget::enableSamplingProfiler() {
   delegate_.enableSamplingProfiler();
 }

diff --git a/packages/react-native/ReactCommon/jsinspector-modern/RuntimeTarget.h b/packages/react-native/ReactCommon/jsinspector-modern/RuntimeTarget.h
@@ -134,6 +134,12 @@ class RuntimeTargetController {
    */
   void notifyDebuggerSessionDestroyed();
 
+  /**
+   * Registers the corresponding RuntimeTarget for Tracing: might enable some
+   * capabilities that will be later used in Tracing Profile.
+   */
+  void registerForTracing();
+
   /**
    * Start sampling profiler for the corresponding RuntimeTarget.
    */
@@ -202,6 +208,12 @@ class JSINSPECTOR_EXPORT RuntimeTarget
       FrontendChannel channel,
       SessionState& sessionState);
 
+  /**
+   * Registers this Runtime for Tracing: might enable some
+   * capabilities that will be later used in Tracing Profile.
+   */
+  void registerForTracing();
+
   /**
    * Start sampling profiler for a particular JavaScript runtime.
    */

diff --git a/packages/react-native/ReactCommon/jsinspector-modern/tracing/PerformanceTracer.cpp b/packages/react-native/ReactCommon/jsinspector-modern/tracing/PerformanceTracer.cpp
@@ -188,6 +188,10 @@ void PerformanceTracer::reportProcess(uint64_t id, const std::string& name) {
   });
 }
 
+void PerformanceTracer::reportJavaScriptThread() {
+  reportThread(oscompat::getCurrentThreadId(), "JavaScript");
+}
+
 void PerformanceTracer::reportThread(uint64_t id, const std::string& name) {
   if (!tracing_) {
     return;

diff --git a/packages/react-native/ReactCommon/jsinspector-modern/tracing/PerformanceTracer.h b/packages/react-native/ReactCommon/jsinspector-modern/tracing/PerformanceTracer.h
@@ -88,6 +88,12 @@ class PerformanceTracer {
    */
   void reportThread(uint64_t id, const std::string& name);
 
+  /**
+   * Should only be called from the JavaScript thread, will buffer metadata
+   * Trace Event.
+   */
+  void reportJavaScriptThread();
+
  private:
   PerformanceTracer();
   PerformanceTracer(const PerformanceTracer&) = delete;