fix: show idle GPU utilization in systems table (#2312)

internal/hub/systems/system.go

@@ -272,7 +272,15 @@ func (sys *System) createRecords(data *system.CombinedData) (*core.Record, error
 
 		// update system record (do this last because it triggers alerts and we need above records to be inserted first)
 		systemRecord.Set("status", up)
-		systemRecord.Set("info", data.Info)
+		// Distinguish an idle GPU from a system without GPU data (#2312)
+		info := struct {
+			system.Info
+			GpuPct *float64 `json:"g,omitempty"`
+		}{Info: data.Info}
+		if len(data.Stats.GPUData) > 0 {
+			info.GpuPct = &data.Info.GpuPct
+		}
+		systemRecord.Set("info", info)
 		if err := txApp.SaveNoValidate(systemRecord); err != nil {
 			return err
 		}

internal/hub/systems/system_gpu_test.go

@@ -0,0 +1,44 @@
+//go:build testing
+
+package systems
+
+import (
+	"testing"
+
+	"github.com/henrygd/beszel/internal/entities/system"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCreateRecordsGPUUtilization(t *testing.T) {
+	sys, app := newTestSystemWithHub(t)
+	for _, tc := range []struct {
+		name  string
+		gpu   bool
+		usage float64
+	}{
+		{"no GPU", false, 0},
+		{"active GPU", true, 42.5},
+		{"idle GPU", true, 0},
+		{"GPU removed", false, 0},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			data := &system.CombinedData{Info: system.Info{GpuPct: tc.usage, Cpu: 12.5}}
+			if tc.gpu {
+				data.Stats.GPUData = map[string]system.GPUData{"0": {Name: "GPU", Usage: tc.usage}}
+			}
+			_, err := sys.createRecords(data)
+			require.NoError(t, err)
+			record, err := app.FindRecordById("systems", sys.Id)
+			require.NoError(t, err)
+			var info map[string]any
+			require.NoError(t, record.UnmarshalJSONField("info", &info))
+			assert.Equal(t, 12.5, info["cpu"])
+			if tc.gpu {
+				assert.Equal(t, tc.usage, info["g"])
+			} else {
+				assert.NotContains(t, info, "g")
+			}
+		})
+	}
+}

internal/site/src/components/systems-table/systems-table-columns.tsx

@@ -193,7 +193,7 @@ export function SystemsTableColumns(viewMode: "table" | "grid"): ColumnDef<Syste
 			header: sortableHeader,
 		},
 		{
-			accessorFn: ({ info }) => info.g || undefined,
+			accessorFn: ({ info }) => info.g,
 			id: "gpu",
 			name: () => "GPU",
 			cell: (info) => {