feat: add cpu socket number in cpu.topology

Signed-off-by: AhmedGrati <ahmedgrati1999@gmail.com>

docs/usage/customization-guide.md

@@ -867,6 +867,7 @@ The following features are available for matching:
 |                  |              | **`bf.enabled`** | bool | `true` if Intel SST-BF (Intel Speed Select Technology - Base frequency) has been enabled, otherwise does not exist |
 | **`cpu.topology`** | attribute  |          |            | CPU topology related features |
 | | |          **`hardware_multithreading`** | bool       | Hardware multithreading, such as Intel HTT, is enabled |
+| | |          **`socket_count`**            | int        | Number of CPU Sockets |
 | **`cpu.coprocessor`** | attribute |        |            | CPU Coprocessor related features |
 | | |          **`nx_gzip`**                 | bool       | Nest Accelerator GZIP support is enabled |
 | **`kernel.config`** | attribute |          |            | Kernel configuration options |

source/cpu/cpu.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"os"
 	"strconv"
+	"strings"
 
 	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/klog/v2"
@@ -276,9 +277,38 @@ func discoverTopology() map[string]string {
 		features["hardware_multithreading"] = strconv.FormatBool(ht)
 	}
 
+	if socketCount, err := getCPUSocketCount(); err != nil {
+		klog.ErrorS(err, "failed to get sockets count")
+	} else {
+		features["socket_count"] = strconv.FormatInt(socketCount, 10)
+	}
+
 	return features
 }
 
+func getCPUSocketCount() (int64, error) {
+	files, err := os.ReadDir(hostpath.SysfsDir.Path("bus/cpu/devices"))
+	if err != nil {
+		return 0, err
+	}
+
+	uniquePhysicalIDs := sets.NewString()
+
+	for _, file := range files {
+		// Try to read physical_package_id from topology
+		physicalID, err := os.ReadFile(hostpath.SysfsDir.Path("bus/cpu/devices", file.Name(), "topology/physical_package_id"))
+		if err != nil {
+			return 0, err
+		}
+		id := strings.TrimSpace(string(physicalID))
+		if err != nil {
+			return 0, err
+		}
+		uniquePhysicalIDs.Insert(id)
+	}
+	return int64(uniquePhysicalIDs.Len()), nil
+}
+
 // Check if any (online) CPUs have thread siblings
 func haveThreadSiblings() (bool, error) {