feat: add NPU load to /v1/metrics

agent/internal/httpapi/extras.go

@@ -115,6 +115,11 @@ func (s *Server) handleMetrics(w http.ResponseWriter, r *http.Request) {
 	} else {
 		resp["disk_io"] = map[string]any{"error": err.Error()}
 	}
+	if npu, err := metrics.ReadNPULoad(); err == nil {
+		resp["npu"] = npu
+	} else {
+		resp["npu"] = map[string]any{"error": err.Error()}
+	}
 
 	media := map[string]any{"supported": s.proc != nil && s.proc.Enabled()}
 	if s.proc == nil || !s.proc.Enabled() {

agent/internal/httpapi/preview.go

@@ -3,10 +3,7 @@ package httpapi
 import (
 	"encoding/json"
 	"net/http"
-	"os"
-	"path/filepath"
 	"strconv"
-	"strings"
 )
 
 type previewChannel struct {

agent/internal/metrics/metrics.go

@@ -261,3 +261,43 @@ func ParseLoadAvg(data string) (LoadAvg, error) {
 	}
 	return LoadAvg{One: one, Five: five, Fifteen: fifteen}, nil
 }
+
+type NPULoad struct {
+	UsagePct float64 `json:"usage_pct"`
+}
+
+func ReadNPULoad() (*NPULoad, error) {
+	f, err := os.Open("/proc/rknpu/load")
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	scanner := bufio.NewScanner(f)
+	var total, idle float64
+	for scanner.Scan() {
+		line := scanner.Text()
+		parts := strings.Split(line, "%")
+		for _, p := range parts {
+			p = strings.TrimSpace(p)
+			if idx := strings.LastIndex(p, " "); idx >= 0 {
+				p = p[idx+1:]
+			}
+			if strings.HasSuffix(p, "%") {
+				continue
+			}
+			v, err := strconv.ParseFloat(strings.TrimSpace(p), 64)
+			if err == nil {
+				total += 100
+				idle += v
+			}
+		}
+	}
+	if total == 0 {
+		return nil, ErrNotSupported
+	}
+	usage := 100 - (idle / total * 100)
+	if usage < 0 {
+		usage = 0
+	}
+	return &NPULoad{UsagePct: usage}, nil
+}