Start power calibration from full GPU TDP

audit/internal/platform/benchmark.go

@@ -3126,7 +3126,7 @@ func runBenchmarkPowerCalibration(
 		if defaultLimitW <= 0 {
 			defaultLimitW = originalLimitW
 		}
-		appliedLimitW := originalLimitW
+		appliedLimitW := initialBenchmarkCalibrationLimitW(info)
 		if appliedLimitW <= 0 {
 			appliedLimitW = defaultLimitW
 		}
@@ -3475,6 +3475,24 @@ func roundTo5W(w int) int {
 	return ((w + 2) / 5) * 5
 }
 
+func initialBenchmarkCalibrationLimitW(info benchmarkGPUInfo) int {
+	defaultLimitW := int(math.Round(info.DefaultPowerLimitW))
+	currentLimitW := int(math.Round(info.PowerLimitW))
+	maxLimitW := int(math.Round(info.MaxPowerLimitW))
+
+	startW := defaultLimitW
+	if startW <= 0 {
+		startW = currentLimitW
+	}
+	if startW <= 0 {
+		startW = maxLimitW
+	}
+	if maxLimitW > 0 && startW > maxLimitW {
+		startW = maxLimitW
+	}
+	return startW
+}
+
 // meanFanRPM returns the average RPM across a set of fan readings.
 func meanFanRPM(fans []FanReading) float64 {
 	if len(fans) == 0 {

audit/internal/platform/benchmark_test.go

@@ -197,6 +197,59 @@ func TestNormalizeNvidiaBenchmarkOptionsPreservesRunNCCLChoice(t *testing.T) {
 	}
 }
 
+func TestInitialBenchmarkCalibrationLimitW(t *testing.T) {
+	t.Parallel()
+
+	cases := []struct {
+		name string
+		info benchmarkGPUInfo
+		want int
+	}{
+		{
+			name: "prefers default tdp over current derated limit",
+			info: benchmarkGPUInfo{
+				PowerLimitW:        500,
+				DefaultPowerLimitW: 600,
+				MaxPowerLimitW:     600,
+			},
+			want: 600,
+		},
+		{
+			name: "caps default tdp to reported max limit",
+			info: benchmarkGPUInfo{
+				PowerLimitW:        500,
+				DefaultPowerLimitW: 700,
+				MaxPowerLimitW:     650,
+			},
+			want: 650,
+		},
+		{
+			name: "falls back to current limit when default missing",
+			info: benchmarkGPUInfo{
+				PowerLimitW:    525,
+				MaxPowerLimitW: 600,
+			},
+			want: 525,
+		},
+		{
+			name: "falls back to max limit when only that is known",
+			info: benchmarkGPUInfo{
+				MaxPowerLimitW: 575,
+			},
+			want: 575,
+		},
+	}
+
+	for _, tc := range cases {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			if got := initialBenchmarkCalibrationLimitW(tc.info); got != tc.want {
+				t.Fatalf("initialBenchmarkCalibrationLimitW(%+v)=%d want %d", tc.info, got, tc.want)
+			}
+		})
+	}
+}
+
 func TestParseBenchmarkBurnLog(t *testing.T) {
 	t.Parallel()