Capture Node execution async ID with samples (#189)

Author: szegedi

bindings/profilers/wall.cc

@@ -321,7 +321,8 @@ void SignalHandler::HandleProfilerSignal(int sig,
   auto time_from = Now();
   old_handler(sig, info, context);
   auto time_to = Now();
-  prof->PushContext(time_from, time_to, cpu_time);
+  double async_id = node::AsyncHooksGetExecutionAsyncId(isolate);
+  prof->PushContext(time_from, time_to, cpu_time, async_id);
 }
 #else
 class SignalHandler {
@@ -388,6 +389,7 @@ ContextsByNode WallProfiler::GetContextsByNode(CpuProfile* profile,
   auto contextKey = Nan::New<v8::String>("context").ToLocalChecked();
   auto timestampKey = Nan::New<v8::String>("timestamp").ToLocalChecked();
   auto cpuTimeKey = Nan::New<v8::String>("cpuTime").ToLocalChecked();
+  auto asyncIdKey = Nan::New<v8::String>("asyncId").ToLocalChecked();
   auto V8toEpochOffset = GetV8ToEpochOffset();
   auto lastCpuTime = startCpuTime;
 
@@ -457,6 +459,9 @@ ContextsByNode WallProfiler::GetContextsByNode(CpuProfile* profile,
                 Nan::New<v8::Number>(sampleContext.cpu_time - lastCpuTime));
             lastCpuTime = sampleContext.cpu_time;
           }
+          Nan::Set(timedContext,
+                   asyncIdKey,
+                   Nan::New<v8::Number>(sampleContext.async_id));
           Nan::Set(array, array->Length(), timedContext);
         }
 
@@ -1003,14 +1008,15 @@ NAN_METHOD(WallProfiler::Dispose) {
 
 void WallProfiler::PushContext(int64_t time_from,
                                int64_t time_to,
-                               int64_t cpu_time) {
+                               int64_t cpu_time,
+                               double async_id) {
   // Be careful this is called in a signal handler context therefore all
   // operations must be async signal safe (in particular no allocations).
   // Our ring buffer avoids allocations.
   auto context = curContext_.load(std::memory_order_relaxed);
   std::atomic_signal_fence(std::memory_order_acquire);
   if (contexts_.size() < contexts_.capacity()) {
-    contexts_.push_back({*context, time_from, time_to, cpu_time});
+    contexts_.push_back({*context, time_from, time_to, cpu_time, async_id});
     std::atomic_fetch_add_explicit(
         reinterpret_cast<std::atomic<uint32_t>*>(&fields_[kSampleCount]),
         1U,

bindings/profilers/wall.hh

@@ -82,6 +82,7 @@ class WallProfiler : public Nan::ObjectWrap {
     int64_t time_from;
     int64_t time_to;
     int64_t cpu_time;
+    double async_id;
   };
 
   using ContextBuffer = std::vector<SampleContext>;
@@ -118,7 +119,10 @@ class WallProfiler : public Nan::ObjectWrap {
 
   v8::Local<v8::Value> GetContext(v8::Isolate*);
   void SetContext(v8::Isolate*, v8::Local<v8::Value>);
-  void PushContext(int64_t time_from, int64_t time_to, int64_t cpu_time);
+  void PushContext(int64_t time_from,
+                   int64_t time_to,
+                   int64_t cpu_time,
+                   double async_id);
   Result StartImpl();
   std::string StartInternal();
   Result StopImpl(bool restart, v8::Local<v8::Value>& profile);

ts/src/profile-serializer.ts

@@ -326,6 +326,7 @@ function updateTimeProfile(prof: TimeProfile): TimeProfile {
           context: {},
           timestamp: BigInt(0),
           cpuTime: prof.nonJSThreadsCpuTime,
+          asyncId: -1,
         },
       ],
     };

ts/src/v8-types.ts

@@ -41,6 +41,7 @@ export interface TimeProfileNodeContext {
   context: object;
   timestamp: bigint; // end of sample taking; in microseconds since epoch
   cpuTime: number; // cpu time in nanoseconds
+  asyncId: number; // async_hooks.executionAsyncId() at the time of sample taking
 }
 
 export interface TimeProfileNode extends ProfileNode {

ts/test/test-time-profiler.ts

@@ -135,6 +135,10 @@ describe('Time Profiler', () => {
         if (!context) {
           return {};
         }
+        assert(
+          typeof context.asyncId === 'number',
+          'context.asyncId should be a number'
+        );
         const labels: LabelSet = {};
         for (const [key, value] of Object.entries(context.context)) {
           if (typeof value === 'string') {