fix ratio calculation

Author: mblos

internal/knowledge/extractor/plugins/compute/flavor_groups.go

@@ -141,7 +141,11 @@ func (e *FlavorGroupExtractor) Extract() ([]plugins.Feature, error) {
 		smallest := flavors[len(flavors)-1]
 
 		// Compute RAM/core ratio (MiB per vCPU)
+		// Use cross-multiplication to detect if ratios truly differ, avoiding integer truncation.
+		// Two ratios mem1/vcpus1 == mem2/vcpus2 iff mem1*vcpus2 == mem2*vcpus1
+		var refMemory, refVCPUs uint64
 		var minRatio, maxRatio uint64 = ^uint64(0), 0
+		allSameRatio := true
 		for _, f := range flavors {
 			if f.VCPUs == 0 {
 				continue // Skip flavors with 0 vCPUs to avoid division by zero
@@ -153,12 +157,19 @@ func (e *FlavorGroupExtractor) Extract() ([]plugins.Feature, error) {
 			if ratio > maxRatio {
 				maxRatio = ratio
 			}
+			// Check if ratio matches reference using cross-multiplication
+			if refVCPUs == 0 {
+				refMemory, refVCPUs = f.MemoryMB, f.VCPUs
+			} else if refMemory*f.VCPUs != f.MemoryMB*refVCPUs {
+				allSameRatio = false
+			}
 		}
 
 		var ramCoreRatio, ramCoreRatioMin, ramCoreRatioMax *uint64
-		if minRatio == maxRatio && maxRatio != 0 {
+		if allSameRatio && refVCPUs != 0 {
 			// All flavors have the same ratio
-			ramCoreRatio = &minRatio
+			computedRatio := refMemory / refVCPUs
+			ramCoreRatio = &computedRatio
 		} else if maxRatio != 0 {
 			// Flavors have different ratios
 			ramCoreRatioMin = &minRatio

internal/scheduling/reservations/commitments/api_info_test.go

@@ -102,7 +102,7 @@ func TestHandleInfo_HasCapacityEqualsHandlesCommitments(t *testing.T) {
 			"ramCoreRatio":   4096, // Fixed: 4096 MiB per vCPU for all flavors
 		},
 		{
-			// Group with variable ratio - should NOT accept commitments (HasCapacity=true, HandlesCommitments=false)
+			// Group with variable ratio - should NOT accept commitments (HasCapacity=false, HandlesCommitments=false)
 			"name": "v2_variable",
 			"flavors": []map[string]interface{}{
 				{"name": "v2_c4_m8", "vcpus": 4, "memoryMB": 8192, "diskGB": 50},    // 2048 MiB/vCPU

internal/scheduling/reservations/commitments/flavor_group_eligibility.go

@@ -22,13 +22,10 @@ func FlavorGroupCommitmentRejectionReason(fg *compute.FlavorGroupFeature) string
 	if FlavorGroupAcceptsCommitments(fg) {
 		return ""
 	}
-	var minRatio, maxRatio uint64
-	if fg.RamCoreRatioMin != nil {
-		minRatio = *fg.RamCoreRatioMin
-	}
-	if fg.RamCoreRatioMax != nil {
-		maxRatio = *fg.RamCoreRatioMax
+	// Differentiate between missing ratio metadata and variable ratio
+	if fg.RamCoreRatioMin == nil && fg.RamCoreRatioMax == nil {
+		return fmt.Sprintf("flavor group %q has no computable RAM/core ratio metadata and does not accept commitments", fg.Name)
 	}
 	return fmt.Sprintf("flavor group %q has variable RAM/core ratio (min=%d, max=%d) and does not accept commitments",
-		fg.Name, minRatio, maxRatio)
+		fg.Name, *fg.RamCoreRatioMin, *fg.RamCoreRatioMax)
 }