Function CoresForNode

pkg/cpu/cpu_linux.go:191–270

(ctx context.Context, nodeID int)

}

func CoresForNode(ctx context.Context, nodeID int) ([]*ProcessorCore, error) {
	// The /sys/devices/system/node/nodeX directory contains a subdirectory
	// called 'cpuX' for each logical processor assigned to the node. Each of
	// those subdirectories contains a topology subdirectory which has a
	// core_id file that indicates the 0-based identifier of the physical core
	// the logical processor (hardware thread) is on.
	paths := linuxpath.New(ctx)
	path := filepath.Join(
		paths.SysDevicesSystemNode,
		fmt.Sprintf("node%d", nodeID),
	)
	cores := make([]*ProcessorCore, 0)

	findCoreByID := func(coreID int) *ProcessorCore {
		for _, c := range cores {
			if c.ID == coreID {
				return c
			}
		}

		c := &ProcessorCore{
			ID:                coreID,
			LogicalProcessors: []int{},
		}
		cores = append(cores, c)
		return c
	}

	files, err := os.ReadDir(path)
	if err != nil {
		return nil, err
	}
	for _, file := range files {
		filename := file.Name()
		if !strings.HasPrefix(filename, "cpu") {
			continue
		}
		if filename == "cpumap" || filename == "cpulist" {
			// There are two files in the node directory that start with 'cpu'
			// but are not subdirectories ('cpulist' and 'cpumap'). Ignore
			// these files.
			continue
		}
		// Grab the logical processor ID by cutting the integer from the
		// /sys/devices/system/node/nodeX/cpuX filename
		cpuPath := filepath.Join(path, filename)
		procID, err := strconv.Atoi(filename[3:])
		if err != nil {
			log.Warn(ctx,
				"failed to determine procID from %s. Expected integer after 3rd char.",
				filename,
			)
			continue
		}
		onlineFilePath := filepath.Join(cpuPath, onlineFile)
		if _, err := os.Stat(onlineFilePath); err == nil {
			if util.SafeIntFromFile(ctx, onlineFilePath) == 0 {
				continue