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>

2 files changed, 166 insertions, 0 deletions

diff --git a/tools/numap/internal/sysfs/parse.go b/tools/numap/internal/sysfs/parse.go
new file mode 100644
index 0000000..d518653
--- /dev/null
+++ b/tools/numap/internal/sysfs/parse.go
@@ -0,0 +1,21 @@
+package sysfs
+
+import (
+	"io/ioutil"
+	"strconv"
+	"strings"
+)
+
+// ContentUint64 parses the content of a file in sysfs, and convert
+// from hex to uint64.
+func ContentUint64(path string) (uint64, error) {
+	content, err := ioutil.ReadFile(path)
+	if err != nil {
+		return 0, err
+	}
+	result, err := strconv.ParseUint(strings.TrimSpace(string(content)), 0, 64)
+	if err != nil {
+		return 0, err
+	}
+	return result, nil
+}
diff --git a/tools/numap/internal/sysfs/pci.go b/tools/numap/internal/sysfs/pci.go
new file mode 100644
index 0000000..9e714b1
--- /dev/null
+++ b/tools/numap/internal/sysfs/pci.go
@@ -0,0 +1,145 @@
+package sysfs
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+const (
+	sysFsPCIDevicesPath = "/sys/bus/pci/devices/"
+)
+
+type PCIDevice struct {
+	NumaNode             int
+	ID                   string
+	Device, Vendor       uint64
+	SubVendor, SubDevice uint64
+	Class                uint64
+	MSIs                 []int
+}
+
+func ScanPCIDevices() []PCIDevice {
+	devices, err := ioutil.ReadDir(sysFsPCIDevicesPath)
+	if err != nil {
+		panic(err)
+	}
+
+	pciDevices := []PCIDevice{}
+
+	for _, device := range devices {
+		dpath := filepath.Join(sysFsPCIDevicesPath, device.Name())
+		pcid, err := NewPCIDevice(dpath, device.Name())
+		if err != nil {
+			panic(err)
+		}
+		pciDevices = append(pciDevices, pcid)
+	}
+	return pciDevices
+}
+
+func getPCIDeviceClass(path string) (uint64, error) {
+	return ContentUint64(filepath.Join(path, "class"))
+}
+
+func getPCIDeviceVendor(path string) (uint64, error) {
+	return ContentUint64(filepath.Join(path, "vendor"))
+}
+
+func getPCIDeviceId(path string) (uint64, error) {
+	return ContentUint64(filepath.Join(path, "device"))
+}
+
+func getPCIDeviceSubsystemDevice(path string) (uint64, error) {
+	return ContentUint64(filepath.Join(path, "subsystem_device"))
+}
+
+func getPCIDeviceSubsystemVendor(path string) (uint64, error) {
+	return ContentUint64(filepath.Join(path, "subsystem_vendor"))
+}
+
+func getPCIDeviceNumaNode(path string) int {
+	content, err := ioutil.ReadFile(filepath.Join(path, "numa_node"))
+	if err != nil {
+		panic(err)
+	}
+	nodeNum, err := strconv.Atoi(strings.TrimSpace(string(content)))
+	if err != nil {
+		panic(err)
+	}
+	return nodeNum
+}
+
+func getPCIDeviceMSIx(p string) []int {
+	g := fmt.Sprintf("%s/*", filepath.Join(p, "msi_irqs"))
+	files, err := filepath.Glob(g)
+	if err != nil {
+		panic(err)
+	}
+	if len(files) == 0 {
+		return []int{}
+	}
+
+	msix := []int{}
+
+	for _, f := range files {
+		content, err := ioutil.ReadFile(f)
+		if err != nil {
+			panic(err)
+		}
+		if strings.TrimSpace(string(content)) == "msix" {
+			base := path.Base(f)
+			v, err := strconv.Atoi(base)
+			if err != nil {
+				panic(err)
+			}
+			msix = append(msix, v)
+		}
+	}
+	return msix
+}
+
+func NewPCIDevice(path, name string) (PCIDevice, error) {
+	nodeNum := getPCIDeviceNumaNode(path)
+
+	device, err := getPCIDeviceId(path)
+	if err != nil {
+		return PCIDevice{}, err
+	}
+
+	vendor, err := getPCIDeviceVendor(path)
+	if err != nil {
+		return PCIDevice{}, err
+	}
+
+	subvendor, err := getPCIDeviceSubsystemVendor(path)
+	if err != nil {
+		return PCIDevice{}, err
+	}
+
+	subdevice, err := getPCIDeviceSubsystemDevice(path)
+	if err != nil {
+		return PCIDevice{}, err
+	}
+
+	deviceClass, err := getPCIDeviceClass(path)
+	if err != nil {
+		return PCIDevice{}, err
+	}
+
+	msix := getPCIDeviceMSIx(path)
+
+	return PCIDevice{
+		ID:        name,
+		Device:    device,
+		Class:     deviceClass,
+		NumaNode:  nodeNum,
+		Vendor:    vendor,
+		SubVendor: subvendor,
+		SubDevice: subdevice,
+		MSIs:      msix,
+	}, nil
+}