feat(tools/numap): add a tool to report NUMA topology of a host

The tool maps the various PCI devices to the NUMA node they are attached
to and print the result to STDOUT in JSON.

Only ethernet, NVMe and GPU devices are accounted for at the moment.

Change-Id: If32c805e61211f0ef4838a82eabc70d7fc1985fe
Reviewed-on: https://cl.fcuny.net/c/world/+/453
Tested-by: CI
Reviewed-by: Franck Cuny <franck@fcuny.net>

1 files changed, 116 insertions, 0 deletions

diff --git a/tools/numap/numa.go b/tools/numap/numa.go
new file mode 100644
index 0000000..402ea1d
--- /dev/null
+++ b/tools/numap/numa.go
@@ -0,0 +1,116 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"golang.fcuny.net/numap/internal/hwids"
+	"golang.fcuny.net/numap/internal/sysfs"
+)
+
+const (
+	node_root      = "/sys/devices/system/node/node*"
+	CLASS_NVMe     = 67586
+	CLASS_ETHERNET = 131072
+	CLASS_GPU      = 197120
+)
+
+type node struct {
+	Name       string      `json:"name"`
+	Path       string      `json:"path"`
+	CpuList    string      `json:"cpulist"`
+	PCIDevices []PCIDevice `json:"pci_devices"`
+}
+
+type PCIDevice struct {
+	Vendor string `json:"vendor"`
+	Name   string `json:"name"`
+}
+
+func findNodes(hwdb hwids.PciDevices) (map[string]node, error) {
+	nodes := make(map[string]node)
+
+	files, err := filepath.Glob(node_root)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to find NUMA nodes under %s: %+v", node_root, err)
+	}
+	if len(files) == 0 {
+		return nil, fmt.Errorf("Could not find NUMA node in %s", node_root)
+	}
+
+	for _, f := range files {
+		n, err := newNode(f)
+		if err != nil {
+			return make(map[string]node), err
+		}
+		nodes[n.Name] = n
+	}
+
+	r, err := mapPCIDevicesToNumaNode(hwdb)
+	if err != nil {
+		panic(err)
+	}
+	for k, v := range r {
+		nodeName := fmt.Sprintf("node%d", k)
+		n := nodes[nodeName]
+		n.PCIDevices = v
+		nodes[nodeName] = n
+	}
+	return nodes, nil
+}
+
+func mapPCIDevicesToNumaNode(hwdb hwids.PciDevices) (map[int][]PCIDevice, error) {
+	devices := sysfs.ScanPCIDevices()
+	r := map[int][]PCIDevice{}
+
+	for _, d := range devices {
+		if d.Class == CLASS_NVMe || d.Class == CLASS_ETHERNET || d.Class == CLASS_GPU {
+			_, ok := hwdb[uint16(d.Vendor)]
+			if ok {
+				desc := hwdb[uint16(d.Vendor)]
+				var vendor, name string
+				for _, m := range desc {
+					if uint64(m.Device) == d.Device && uint64(m.Vendor) == d.Vendor {
+						vendor = m.VendorName
+						name = m.DeviceName
+						break
+					}
+				}
+				pciDevice := PCIDevice{
+					Vendor: vendor,
+					Name:   name,
+				}
+				r[d.NumaNode] = append(r[d.NumaNode], pciDevice)
+			}
+		}
+	}
+	return r, nil
+}
+
+func newNode(p string) (node, error) {
+	_, name := path.Split(p)
+
+	cpulist, err := cpuList(p)
+	if err != nil {
+		return node{}, err
+	}
+
+	return node{
+		Name:       name,
+		Path:       p,
+		CpuList:    cpulist,
+		PCIDevices: []PCIDevice{},
+	}, nil
+}
+
+func cpuList(p string) (string, error) {
+	lpath := filepath.Join(p, "cpulist")
+	c, err := ioutil.ReadFile(lpath)
+	if err != nil {
+		return "", fmt.Errorf("Failed to open %s: %+v", lpath, err)
+	}
+	return strings.TrimRight(string(c), "\n"), nil
+}