Change CPUSocketMap creation, adapt coalesceEvents to leverage updated map

cmd/metrics/event_frame.go

@@ -219,26 +219,37 @@ func coalesceEvents(allEvents []Event, scope string, granularity string, metadat
 			// create a mapping of cpu numbers to event indices
 			var cpuMap map[int]int
 
-			// if cpu range is specified, use it to determine the number of cpus
-			// otherwise, use the number of sockets, cores per socket, and threads per core
-			// to determine the number of cpus
+			// create a list of CPU IDs targeted for profiling
+			var cpuIDs []int
+
+			// if CPU range is specified, use it to determine the number of CPUs
+			// otherwise, use the CPUSocketMap structure to determine the online CPUs
+			// then create a list of CPU IDs for the targeted CPUs
 			if flagCpuRange != "" {
-				cpuList, err := util.SelectiveIntRangeToIntList(flagCpuRange)
+				var err error
+				cpuIDs, err = util.SelectiveIntRangeToIntList(flagCpuRange)
 				if err != nil {
 					return nil, fmt.Errorf("failed to parse cpu range: %w", err)
 				}
-				numCPUs = len(cpuList)
-				cpuMap = make(map[int]int, numCPUs)
-				for i, cpu := range cpuList {
-					cpuMap[cpu] = i
-				}
+				numCPUs = len(cpuIDs)
 			} else {
-				numCPUs = metadata.SocketCount * metadata.CoresPerSocket * metadata.ThreadsPerCore
-				cpuMap = make(map[int]int, numCPUs)
-				for i := 0; i < numCPUs; i++ {
-					cpuMap[i] = i
+				numCPUs = len(metadata.CPUSocketMap)
+
+				for cpuID := range metadata.CPUSocketMap {
+					cpuIDs = append(cpuIDs, cpuID)
 				}
 			}
+
+			// create a mapping of the target CPU IDs to their event indices
+			cpuMap = make(map[int]int, numCPUs)
+
+			// sort the CPU IDs
+			slices.Sort(cpuIDs)
+
+			// place the sorted CPU IDs into the mapping
+			for idx, cpuID := range cpuIDs {
+				cpuMap[cpuID] = idx
+			}
 			// note: if some cores have been off-lined, this may cause an issue because 'perf' seems
 			// to still report events for those cores
 			newEvents := make([][]Event, numCPUs)

cmd/metrics/metadata.go

@@ -85,7 +85,7 @@ func LoadMetadata(myTarget target.Target, noRoot bool, noSystemSummary bool, per
 		metadata.ThreadsPerCore = 1
 	}
 	// CPUSocketMap (from cpuInfo)
-	metadata.CPUSocketMap = createCPUSocketMap(metadata.CoresPerSocket, metadata.SocketCount, metadata.ThreadsPerCore == 2)
+	metadata.CPUSocketMap = createCPUSocketMap(cpuInfo)
 	// Model Name (from cpuInfo)
 	metadata.ModelName = cpuInfo[0]["model name"]
 	// Vendor (from cpuInfo)
@@ -709,29 +709,18 @@ func getKernelVersion(scriptOutputs map[string]script.ScriptOutput) (version str
 }
 
 // createCPUSocketMap creates a mapping of logical CPUs to their corresponding sockets.
-// The function takes the number of cores per socket, the number of sockets, and a boolean indicating whether hyperthreading is enabled.
+// The function traverses the output of /proc/cpuinfo and examines the "processor" and "physical id" fields.
 // It returns a map where the key is the logical CPU index and the value is the socket index.
-func createCPUSocketMap(coresPerSocket int, sockets int, hyperthreading bool) (cpuSocketMap map[int]int) {
+func createCPUSocketMap(cpuInfo []map[string]string) (cpuSocketMap map[int]int) {
 	// Create an empty map
 	cpuSocketMap = make(map[int]int)
 
-	// Calculate the total number of logical CPUs
-	totalCPUs := coresPerSocket * sockets
-	if hyperthreading {
-		totalCPUs *= 2 // hyperthreading doubles the number of logical CPUs
-	}
-	// Assign each CPU to a socket
-	for i := range totalCPUs {
-		// Assume that the CPUs are evenly distributed between the sockets
-		socket := i / coresPerSocket
-		if hyperthreading {
-			// With non-adjacent hyperthreading, the second logical CPU of each core is in the second half
-			if i >= totalCPUs/2 {
-				socket = (i - totalCPUs/2) / coresPerSocket
-			}
-		}
-		// Store the mapping
-		cpuSocketMap[i] = socket
+	// Iterate over the CPU info to create the mapping
+	for idx := range cpuInfo {
+		procID, _ := strconv.Atoi(cpuInfo[idx]["processor"])
+		physID, _ := strconv.Atoi(cpuInfo[idx]["physical id"])
+		cpuSocketMap[procID] = physID
 	}
+
 	return cpuSocketMap
 }