Add CPU id to trace and trace metadata (#249)

host/host.go

@@ -55,4 +55,5 @@ type Trace struct {
 	TID              libpf.PID
 	APMTraceID       libpf.APMTraceID
 	APMTransactionID libpf.APMTransactionID
+	CPU              int
 }

reporter/iface.go

@@ -36,6 +36,7 @@ type TraceEventMeta struct {
 	Comm           string
 	APMServiceName string
 	PID, TID       libpf.PID
+	CPU            int
 }
 
 type TraceReporter interface {

tracehandler/tracehandler.go

@@ -126,6 +126,7 @@ func (m *traceHandler) HandleTrace(bpfTrace *host.Trace) {
 		PID:            bpfTrace.PID,
 		TID:            bpfTrace.TID,
 		APMServiceName: "", // filled in below
+		CPU:            bpfTrace.CPU,
 	}
 
 	if !m.reporter.SupportsReportTraceEvent() {

tracer/events.go

@@ -134,7 +134,7 @@ func startPerfEventMonitor(ctx context.Context, perfEventMap *ebpf.Map,
 // calls. Returns a function that can be called to retrieve perf event array
 // error counts.
 func startPollingPerfEventMonitor(ctx context.Context, perfEventMap *ebpf.Map,
-	pollFrequency time.Duration, perCPUBufferSize int, triggerFunc func([]byte),
+	pollFrequency time.Duration, perCPUBufferSize int, triggerFunc func([]byte, int),
 ) func() (lost, noData, readError uint64) {
 	eventReader, err := perf.NewReader(perfEventMap, perCPUBufferSize)
 	if err != nil {
@@ -178,7 +178,7 @@ func startPollingPerfEventMonitor(ctx context.Context, perfEventMap *ebpf.Map,
 					noDataCount.Add(1)
 					continue
 				}
-				triggerFunc(data.RawSample)
+				triggerFunc(data.RawSample, data.CPU)
 			}
 		}
 	}()

tracer/tracer.go

@@ -841,7 +841,7 @@ func (t *Tracer) eBPFMetricsCollector(
 //
 // If the raw trace contains a kernel stack ID, the kernel stack is also
 // retrieved and inserted at the appropriate position.
-func (t *Tracer) loadBpfTrace(raw []byte) *host.Trace {
+func (t *Tracer) loadBpfTrace(raw []byte, cpu int) *host.Trace {
 	frameListOffs := int(unsafe.Offsetof(C.Trace{}.frames))
 
 	if len(raw) < frameListOffs {
@@ -863,6 +863,7 @@ func (t *Tracer) loadBpfTrace(raw []byte) *host.Trace {
 		PID:              libpf.PID(ptr.pid),
 		TID:              libpf.PID(ptr.tid),
 		KTime:            times.KTime(ptr.ktime),
+		CPU:              cpu,
 	}
 
 	// Trace fields included in the hash:
@@ -912,8 +913,8 @@ func (t *Tracer) StartMapMonitors(ctx context.Context, traceOutChan chan *host.T
 	eventMetricCollector := t.startEventMonitor(ctx)
 
 	startPollingPerfEventMonitor(ctx, t.ebpfMaps["trace_events"], t.intervals.TracePollInterval(),
-		t.samplesPerSecond*int(unsafe.Sizeof(C.Trace{})), func(rawTrace []byte) {
-			traceOutChan <- t.loadBpfTrace(rawTrace)
+		t.samplesPerSecond*int(unsafe.Sizeof(C.Trace{})), func(rawTrace []byte, cpu int) {
+			traceOutChan <- t.loadBpfTrace(rawTrace, cpu)
 		})
 
 	pidEvents := make([]uint32, 0)