CPU History, CPU Utilization

util/sys/sys_darwin.go

@@ -4,7 +4,12 @@
 package sys
 
 import (
+	"encoding/binary"
+	"fmt"
+	"sync"
+
 	"github.com/shirou/gopsutil/v4/net"
+	"golang.org/x/sys/unix"
 )
 
 func GetTCPCount() (int, error) {
@@ -22,3 +27,69 @@ func GetUDPCount() (int, error) {
 	}
 	return len(stats), nil
 }
+
+// --- CPU Utilization (macOS native) ---
+
+// sysctl kern.cp_time returns an array of 5 longs: user, nice, sys, idle, intr.
+// We compute utilization deltas without cgo.
+var (
+	cpuMu       sync.Mutex
+	lastTotals  [5]uint64
+	hasLastCPUT bool
+)
+
+func CPUPercentRaw() (float64, error) {
+	raw, err := unix.SysctlRaw("kern.cp_time")
+	if err != nil {
+		return 0, err
+	}
+	// Expect either 5*8 bytes (uint64) or 5*4 bytes (uint32)
+	var out [5]uint64
+	switch len(raw) {
+	case 5 * 8:
+		for i := 0; i < 5; i++ {
+			out[i] = binary.LittleEndian.Uint64(raw[i*8 : (i+1)*8])
+		}
+	case 5 * 4:
+		for i := 0; i < 5; i++ {
+			out[i] = uint64(binary.LittleEndian.Uint32(raw[i*4 : (i+1)*4]))
+		}
+	default:
+		return 0, fmt.Errorf("unexpected kern.cp_time size: %d", len(raw))
+	}
+
+	// user, nice, sys, idle, intr
+	user := out[0]
+	nice := out[1]
+	sysv := out[2]
+	idle := out[3]
+	intr := out[4]
+
+	cpuMu.Lock()
+	defer cpuMu.Unlock()
+
+	if !hasLastCPUT {
+		lastTotals = out
+		hasLastCPUT = true
+		return 0, nil
+	}
+
+	dUser := user - lastTotals[0]
+	dNice := nice - lastTotals[1]
+	dSys := sysv - lastTotals[2]
+	dIdle := idle - lastTotals[3]
+	dIntr := intr - lastTotals[4]
+
+	lastTotals = out
+
+	totald := dUser + dNice + dSys + dIdle + dIntr
+	if totald == 0 {
+		return 0, nil
+	}
+	busy := totald - dIdle
+	pct := float64(busy) / float64(totald) * 100.0
+	if pct > 100 {
+		pct = 100
+	}
+	return pct, nil
+}