[exporter/signalfx] Fix for physical cores and cpus counting in linux (#47550)

Author: akhileshsingh85

.chloggen/otl-3444-signalfx-physical-cpu-cores-fix.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. receiver/filelog)
+component: exporter/signalfx
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fix incorrect `host_physical_cpus` and `host_cpu_cores` values reported on Linux
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [47550]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

exporter/signalfxexporter/internal/hostmetadata/host.go

@@ -8,6 +8,7 @@ package hostmetadata // import "github.com/open-telemetry/opentelemetry-collecto
 
 import (
 	"context"
+	"fmt"
 	"strconv"
 	"time"
 
@@ -52,29 +53,38 @@ func (c *hostCPU) toStringMap() map[string]string {
 func getCPU(ctx context.Context) (info *hostCPU, err error) {
 	info = &hostCPU{}
 
-	// get physical cpu stats
 	var cpus []cpu.InfoStat
 
 	// On Windows this can sometimes take longer than the default timeout (10 seconds).
 	ctx, cancel := context.WithTimeout(ctx, cpuStatsTimeout)
 	defer cancel()
 
+	// get cpu infoStats
 	cpus, err = cpuInfo(ctx)
 	if err != nil {
 		return info, err
 	}
 
-	info.HostPhysicalCPUs = len(cpus)
+	// get physical cpu stats
+	info.HostPhysicalCPUs, err = cpuCounts(ctx, false)
+	if err != nil {
+		return info, err
+	}
 
 	// get logical cpu stats
 	info.HostLogicalCPUs, err = cpuCounts(ctx, true)
 	if err != nil {
 		return info, err
 	}
 
-	// total number of cpu cores
+	// Count physical CPU cores by tracking unique {PhysicalID, CoreID} pairs.
+	physicalCores := make(map[string]bool)
 	for i := range cpus {
-		info.HostCPUCores += int64(cpus[i].Cores)
+		k := fmt.Sprintf("%s,%s", cpus[i].PhysicalID, cpus[i].CoreID)
+		if !physicalCores[k] {
+			physicalCores[k] = true
+			info.HostCPUCores++
+		}
 		// TODO: This is not ideal... if there are different processors
 		// we will only report one of the models... This is unlikely to happen,
 		// but it could

exporter/signalfxexporter/internal/hostmetadata/host_test.go

@@ -32,27 +32,33 @@ func TestGetCPU(t *testing.T) {
 		{
 			name: "successful host cpu info",
 			fixtures: testfixture{
+				// Simulate a Linux host: 2 sockets, 2 cores each, 2 threads per core = 8 logical CPUs.
+				// On Linux, cpu.InfoWithContext returns one InfoStat per logical CPU with Cores=1,
+				// so PhysicalID and CoreID must be set to identify unique physical cores.
 				cpuInfo: func(context.Context) ([]cpu.InfoStat, error) {
 					return []cpu.InfoStat{
-						{
-							ModelName: "testmodelname",
-							Cores:     4,
-						},
-						{
-							ModelName: "testmodelname2",
-							Cores:     4,
-						},
+						{ModelName: "testmodelname", Cores: 1, PhysicalID: "0", CoreID: "0"},
+						{ModelName: "testmodelname", Cores: 1, PhysicalID: "0", CoreID: "0"}, // hyperthreading sibling
+						{ModelName: "testmodelname", Cores: 1, PhysicalID: "0", CoreID: "1"},
+						{ModelName: "testmodelname", Cores: 1, PhysicalID: "0", CoreID: "1"}, // hyperthreading sibling
+						{ModelName: "testmodelname2", Cores: 1, PhysicalID: "1", CoreID: "0"},
+						{ModelName: "testmodelname2", Cores: 1, PhysicalID: "1", CoreID: "0"}, // hyperthreading sibling
+						{ModelName: "testmodelname2", Cores: 1, PhysicalID: "1", CoreID: "1"},
+						{ModelName: "testmodelname2", Cores: 1, PhysicalID: "1", CoreID: "1"}, // hyperthreading sibling
 					}, nil
 				},
-				cpuCounts: func(context.Context, bool) (int, error) {
-					return 2, nil
+				cpuCounts: func(_ context.Context, logical bool) (int, error) {
+					if logical {
+						return 8, nil // 2 sockets * 2 cores * 2 threads
+					}
+					return 2, nil // 2 physical sockets
 				},
 			},
 			wantInfo: map[string]string{
 				"host_physical_cpus": "2",
-				"host_cpu_cores":     "8",
+				"host_cpu_cores":     "4",
 				"host_cpu_model":     "testmodelname2",
-				"host_logical_cpus":  "2",
+				"host_logical_cpus":  "8",
 			},
 		},
 		{
@@ -90,7 +96,7 @@ func TestGetCPU(t *testing.T) {
 				},
 			},
 			wantInfo: map[string]string{
-				"host_physical_cpus": "2",
+				"host_physical_cpus": "0", // cpuCounts(false) fails, HostPhysicalCPUs stays at zero
 				"host_cpu_cores":     "0",
 				"host_cpu_model":     "",
 				"host_logical_cpus":  "0",

exporter/signalfxexporter/internal/hostmetadata/metadata_test.go

@@ -41,8 +41,10 @@ func TestSyncMetadata(t *testing.T) {
 		{
 			name: "all_stats_available",
 			cpuStat: cpu.InfoStat{
-				Cores:     4,
-				ModelName: "testprocessor",
+				Cores:      1,
+				ModelName:  "testprocessor",
+				PhysicalID: "0",
+				CoreID:     "0",
 			},
 			cpuStatErr: nil,
 			memStat: mem.VirtualMemoryStat{
@@ -63,7 +65,7 @@ func TestSyncMetadata(t *testing.T) {
 					ResourceID:    "host1",
 					MetadataDelta: metadata.MetadataDelta{
 						MetadataToUpdate: map[string]string{
-							"host_cpu_cores":      "4",
+							"host_cpu_cores":      "1",
 							"host_cpu_model":      "testprocessor",
 							"host_logical_cpus":   "1",
 							"host_physical_cpus":  "1",
@@ -84,8 +86,10 @@ func TestSyncMetadata(t *testing.T) {
 		{
 			name: "no_host_stats",
 			cpuStat: cpu.InfoStat{
-				Cores:     4,
-				ModelName: "testprocessor",
+				Cores:      1,
+				ModelName:  "testprocessor",
+				PhysicalID: "0",
+				CoreID:     "0",
 			},
 			cpuStatErr: nil,
 			memStat: mem.VirtualMemoryStat{
@@ -102,7 +106,7 @@ func TestSyncMetadata(t *testing.T) {
 					ResourceID:    "host1",
 					MetadataDelta: metadata.MetadataDelta{
 						MetadataToUpdate: map[string]string{
-							"host_cpu_cores":     "4",
+							"host_cpu_cores":     "1",
 							"host_cpu_model":     "testprocessor",
 							"host_logical_cpus":  "1",
 							"host_physical_cpus": "1",