initial support for one intel gpu with intel_gpu_top

agent/gpu_intel.go

@@ -0,0 +1,102 @@
+package agent
+
+import (
+	"encoding/json"
+	"fmt"
+	"os/exec"
+
+	"github.com/henrygd/beszel/internal/entities/system"
+)
+
+const (
+	intelGpuStatsCmd      string = "intel_gpu_top"
+	intelGpuStatsInterval string = "3300" // in milliseconds
+)
+
+type intelGpuStats struct {
+	Power struct {
+		GPU float64 `json:"GPU"`
+	} `json:"power"`
+	Engines map[string]struct {
+		Busy float64 `json:"busy"`
+	} `json:"engines"`
+}
+
+// updateIntelFromStats updates aggregated GPU data from a single intelGpuStats sample
+func (gm *GPUManager) updateIntelFromStats(sample *intelGpuStats) bool {
+	gm.Lock()
+	defer gm.Unlock()
+
+	// only one gpu for now - cmd doesn't provide all by default
+	gpuData, ok := gm.GpuDataMap["0"]
+	if !ok {
+		gpuData = &system.GPUData{Name: "GPU", Engines: make(map[string]float64)}
+		gm.GpuDataMap["0"] = gpuData
+	}
+
+	if sample.Power.GPU > 0 {
+		gpuData.Power += sample.Power.GPU
+	}
+
+	if gpuData.Engines == nil {
+		gpuData.Engines = make(map[string]float64, len(sample.Engines))
+	}
+	for name, engine := range sample.Engines {
+		gpuData.Engines[name] += engine.Busy
+	}
+
+	gpuData.Count++
+	return true
+}
+
+// collectIntelStats executes intel_gpu_top in JSON mode and stream-decodes the array of samples
+func (gm *GPUManager) collectIntelStats() error {
+	cmd := exec.Command(intelGpuStatsCmd, "-s", intelGpuStatsInterval, "-J")
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return err
+	}
+	if err := cmd.Start(); err != nil {
+		return err
+	}
+
+	dec := json.NewDecoder(stdout)
+
+	// Expect a JSON array stream: [ { ... }, { ... }, ... ]
+	tok, err := dec.Token()
+	if err != nil {
+		return err
+	}
+	if delim, ok := tok.(json.Delim); !ok || delim != '[' {
+		return fmt.Errorf("unexpected JSON start token: %v", tok)
+	}
+
+	var sample intelGpuStats
+	for {
+		if dec.More() {
+			// Clear the engines map before decoding
+			if sample.Engines != nil {
+				for k := range sample.Engines {
+					delete(sample.Engines, k)
+				}
+			}
+
+			if err := dec.Decode(&sample); err != nil {
+				return fmt.Errorf("decode intel gpu: %w", err)
+			}
+			gm.updateIntelFromStats(&sample)
+			continue
+		}
+		// Attempt to read closing bracket (will only be present when process exits)
+		tok, err = dec.Token()
+		if err != nil {
+			// When the process is still running, decoder will block in More/Decode; any error here is terminal
+			return err
+		}
+		if delim, ok := tok.(json.Delim); ok && delim == ']' {
+			break
+		}
+	}
+
+	return cmd.Wait()
+}