working intel gpu stats for one gpu

agent/gpu_intel.go

@@ -2,52 +2,101 @@ package agent
 
 import (
 	"encoding/json"
-	"log/slog"
+	"fmt"
+	"os/exec"
 
 	"github.com/henrygd/beszel/internal/entities/system"
 )
 
 const (
 	intelGpuStatsCmd      string = "intel_gpu_top"
-	intelGpuStatsInterval string = "3800" // in milliseconds
+	intelGpuStatsInterval string = "3300" // in milliseconds
 )
 
 type intelGpuStats struct {
 	Power struct {
-		GPU float64 `json:"gpu"`
+		GPU float64 `json:"GPU"`
 	} `json:"power"`
 	Engines map[string]struct {
 		Busy float64 `json:"busy"`
 	} `json:"engines"`
 }
 
-func (gm *GPUManager) parseIntelData(output []byte) bool {
-	slog.Info("Parsing Intel GPU stats")
-	var intelGpuStats intelGpuStats
-	if err := json.Unmarshal(output, &intelGpuStats); err != nil {
-		slog.Error("Error parsing Intel GPU stats", "err", err)
-		return false
-	}
+// 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, len(intelGpuStats.Engines))}
+		gpuData = &system.GPUData{Name: "GPU", Engines: make(map[string]float64)}
 		gm.GpuDataMap["0"] = gpuData
 	}
 
-	if intelGpuStats.Power.GPU > 0 {
-		gpuData.Power += intelGpuStats.Power.GPU
+	if sample.Power.GPU > 0 {
+		gpuData.Power += sample.Power.GPU
 	}
 
-	for name, engine := range intelGpuStats.Engines {
+	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++
-
-	slog.Info("GPU Data", "gpuData", gpuData)
 	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()
+}