init darwin cpu support

Signed-off-by: Nahian Pathan <nahian@me.com>

Author: pixelsoccupied

pkg/cpu/cpu_darwin.go

@@ -0,0 +1,135 @@
+package cpu
+
+import (
+	"fmt"
+	"github.com/pkg/errors"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+var (
+	hasARMArchitecture = false                   // determine if ARM
+	sysctlOutput       = make(map[string]string) // store all the sysctl output
+)
+
+func (i *Info) load() error {
+	err := populateSysctlOutput()
+	if err != nil {
+		return errors.Wrap(err, "unable to populate sysctl map")
+	}
+
+	i.TotalCores = getTotalCores()
+	i.TotalThreads = getTotalThreads()
+	i.Processors = getProcessors()
+
+	return nil
+}
+
+// getProcessors some more info https://developer.apple.com/documentation/kernel/1387446-sysctlbyname/determining_system_capabilities
+func getProcessors() []*Processor {
+	p := make([]*Processor, getProcTopCount())
+	for i, _ := range p {
+		p[i] = new(Processor)
+		p[i].Vendor = sysctlOutput[fmt.Sprintf("hw.perflevel%s.name", strconv.Itoa(i))]
+		p[i].Model = getVendor()
+		p[i].NumCores = getNumberCoresFromPerfLevel(i)
+		p[i].Capabilities = getCapabilities()
+		p[i].Cores = make([]*ProcessorCore, getTotalCores())
+	}
+	return p
+}
+
+// getCapabilities valid for ARM, see https://developer.apple.com/documentation/kernel/1387446-sysctlbyname/determining_instruction_set_characteristics
+func getCapabilities() []string {
+	var caps []string
+
+	// add ARM capabilities
+	if hasARMArchitecture {
+		for cap, isEnabled := range sysctlOutput {
+			if isEnabled == "1" {
+				// capabilities with keys with a common prefix
+				commonPrefix := "hw.optional.arm."
+				if strings.HasPrefix(cap, commonPrefix) {
+					caps = append(caps, strings.TrimPrefix(cap, commonPrefix))
+				}
+				// not following prefix convention but are important
+				if cap == "hw.optional.AdvSIMD_HPFPCvt" {
+					caps = append(caps, "AdvSIMD_HPFPCvt")
+				}
+				if cap == "hw.optional.armv8_crc32" {
+					caps = append(caps, "armv8_crc32")
+				}
+			}
+		}
+
+		// hw.optional.AdvSIMD and hw.optional.floatingpoint are always enabled (see linked doc)
+		caps = append(caps, "AdvSIMD")
+		caps = append(caps, "floatingpoint")
+	}
+
+	return caps
+}
+
+// populateSysctlOutput to populate a map to quickly retrieve values later
+func populateSysctlOutput() error {
+	// get sysctl output
+	o, err := exec.Command("sysctl", "-a").CombinedOutput()
+	if err != nil {
+		return err
+	}
+
+	// clean up and store sysctl output
+	oS := strings.Split(string(o), "\n")
+	for _, l := range oS {
+		if l != "" {
+			s := strings.SplitN(l, ":", 2)
+			k, v := strings.TrimSpace(s[0]), strings.TrimSpace(s[1])
+			sysctlOutput[k] = v
+
+			// see if it's possible to determine if ARM
+			if k == "hw.optional.arm64" && v == "1" {
+				hasARMArchitecture = true
+			}
+		}
+	}
+
+	return nil
+}
+
+func getNumberCoresFromPerfLevel(i int) uint32 {
+	key := fmt.Sprintf("hw.perflevel%s.physicalcpu_max", strconv.Itoa(i))
+	nCores := sysctlOutput[key]
+	return stringToUint32(nCores)
+}
+
+func getVendor() string {
+	v := sysctlOutput["machdep.cpu.brand_string"]
+	return v
+}
+
+func getProcTopCount() int {
+	pC, ok := sysctlOutput["hw.nperflevels"]
+	if !ok {
+		// most likely intel so no performance/efficiency core seperation
+		return 1
+	}
+	i, _ := strconv.Atoi(pC)
+	return i
+}
+
+// num of physical cores
+func getTotalCores() uint32 {
+	nCores := sysctlOutput["hw.physicalcpu_max"]
+	return stringToUint32(nCores)
+}
+
+func getTotalThreads() uint32 {
+	nThreads := sysctlOutput["machdep.cpu.thread_count"]
+	return stringToUint32(nThreads)
+}
+
+func stringToUint32(s string) uint32 {
+	o, _ := strconv.ParseUint(s, 10, 0)
+	return uint32(o)
+}

pkg/cpu/cpu_stub.go

@@ -1,5 +1,5 @@
-//go:build !linux && !windows
-// +build !linux,!windows
+//go:build !linux && !windows && !darwin
+// +build !linux,!windows,!darwin
 
 // Use and distribution licensed under the Apache license version 2.
 //