model: add MLA absorption for glm4moelite (#13810)

* model: add MLA absorption for glm4moelite

Split the combined KV_B tensor into separate K_B and V_B tensors
during conversion, enabling MLA (Multi-head Latent Attention)
absorption which compresses the KV cache for improved efficiency.

* ggml: enable MLA flash attention for GLM-4.7-flash

Add support for gqa_ratio 4 in MLA flash attention kernels. GLM-4.7-flash
uses head size 576 with gqa_ratio 4, which was previously only supported
for gqa_ratio 16 (DeepSeek).

Metal changes:
- Enable head size 576 for flash attention
- Increase simdgroups to 8 for large heads (>=512)
- Add case 8 kernel dispatch for 8 simdgroups

CUDA changes:
- Add gqa_ratio 4 support for head 576/512
- Add tile configs for (576, 512, 4) and (576, 512, 8)
- Add MMA config cases for ncols 4
- Add template instances for ncols2=4

* model: add compatibility validation for glm4moelite architecture

model/model.go

@@ -39,6 +39,13 @@ type Model interface {
 	Config() config
 }
 
+// Validator is an optional interface that models can implement to perform
+// validation after tensors have been loaded. If validation fails, model
+// loading will fail with the returned error.
+type Validator interface {
+	Validate() error
+}
+
 // MultimodalProcessor must be implemented by multimodal models.
 type MultimodalProcessor interface {
 	// EncodeMultimodal processes a single input (such as an image) and
@@ -116,6 +123,13 @@ func New(modelPath string, params ml.BackendParams) (Model, error) {
 	base := Base{b: b, config: m.Config()}
 	v := reflect.ValueOf(m)
 	v.Elem().Set(populateFields(base, v.Elem()))
+
+	if validator, ok := m.(Validator); ok {
+		if err := validator.Validate(); err != nil {
+			return nil, err
+		}
+	}
+
 	return m, nil
 }
 

model/models/glm4moelite/model.go

@@ -1,6 +1,7 @@
 package glm4moelite
 
 import (
+	"errors"
 	"math"
 
 	"github.com/ollama/ollama/fs"
@@ -11,6 +12,8 @@ import (
 	"github.com/ollama/ollama/model/input"
 )
 
+var ErrOldModelFormat = errors.New("this model uses a weight format that is no longer supported; please re-download it")
+
 type Options struct {
 	numExpertsUsed      int
 	numExperts          int
@@ -47,7 +50,9 @@ type Attention struct {
 
 	KVA     *nn.Linear  `gguf:"attn_kv_a_mqa"`
 	KVANorm *nn.RMSNorm `gguf:"attn_kv_a_norm"`
-	KVB     *nn.Linear  `gguf:"attn_kv_b"`
+
+	KB *nn.Linear `gguf:"attn_k_b"`
+	VB *nn.Linear `gguf:"attn_v_b"`
 
 	Output *nn.Linear `gguf:"attn_out,alt:attn_output"`
 }
@@ -78,15 +83,16 @@ func (attn *Attention) Forward(ctx ml.Context, hiddenStates, positions ml.Tensor
 	qRot := opts.applyRotaryPositionEmbeddings(ctx, queryChunks[1], positions)
 	kRot = opts.applyRotaryPositionEmbeddings(ctx, kRot, positions)
 	kPass = attn.KVANorm.Forward(ctx, kPass, opts.eps)
-	kPass = attn.KVB.Forward(ctx, kPass)
 
-	kv := kPass.Reshape(ctx, kPass.Dim(0)/opts.numKVHeads, opts.numKVHeads, seqLength)
-	kvChunks := kv.ChunkSections(ctx, 0, opts.kqNopeHeadDim, opts.vHeadDim)
+	// MLA absorption: absorb K projection into query
+	qPass := queryChunks[0].Permute(ctx, 0, 2, 1, 3)
+	qPassAbsorb := attn.KB.Forward(ctx, qPass).Permute(ctx, 0, 2, 1, 3)
+	query = qRot.Concat(ctx, qPassAbsorb, 0)
 
-	kRot = kRot.Repeat(ctx, 1, queryChunks[0].Dim(1))
-	query = qRot.Concat(ctx, queryChunks[0], 0)
-	key := kRot.Concat(ctx, kvChunks[0], 0)
-	attention := nn.Attention(ctx, query, key, kvChunks[1], opts.kqScale, cache)
+	kPass = kPass.Reshape(ctx, opts.kvLoraRank, 1, seqLength)
+	key := kRot.Concat(ctx, kPass, 0)
+
+	attention := nn.AttentionWithVMLA(ctx, query, key, kPass, nil, attn.VB.Weight, opts.kqScale, cache)
 
 	attention = attention.Reshape(ctx, attention.Dim(0)*attention.Dim(1), seqLength)
 	return attn.Output.Forward(ctx, attention)
@@ -217,8 +223,12 @@ func New(c fs.Config) (model.Model, error) {
 
 	keyLength := int(c.Uint("attention.key_length"))
 	valueLength := int(c.Uint("attention.value_length"))
+	kvLoraRank := int(c.Uint("attention.kv_lora_rank"))
+	qkRopeHeadDim := int(c.Uint("rope.dimension_count"))
 
-	kqScale := 1.0 / math.Sqrt(float64(keyLength))
+	// For MLA absorption, the effective key dimension is kvLoraRank + qkRopeHeadDim
+	mlaKeyLength := kvLoraRank + qkRopeHeadDim
+	kqScale := 1.0 / math.Sqrt(float64(mlaKeyLength))
 
 	var pre []string
 	switch c.String("tokenizer.ggml.pre") {
@@ -279,6 +289,15 @@ func (m Model) Shift(ctx ml.Context, layer int, key, shift ml.Tensor) (ml.Tensor
 	return m.applyRotaryPositionEmbeddings(ctx, key, shift), nil
 }
 
+func (m *Model) Validate() error {
+	for _, layer := range m.Layers {
+		if layer.Attention != nil && (layer.Attention.KB == nil || layer.Attention.VB == nil) {
+			return ErrOldModelFormat
+		}
+	}
+	return nil
+}
+
 func (m *Model) Forward(ctx ml.Context, batch input.Batch) (ml.Tensor, error) {
 	positions := ctx.Input().FromInts(batch.Positions, len(batch.Positions))
 

model/models/glm4moelite/model_test.go

@@ -0,0 +1,73 @@
+package glm4moelite
+
+import (
+	"testing"
+
+	"github.com/ollama/ollama/ml/nn"
+)
+
+func TestValidate(t *testing.T) {
+	tests := []struct {
+		name    string
+		model   *Model
+		wantErr bool
+	}{
+		{
+			name: "valid model with KB and VB",
+			model: &Model{
+				Layers: []Layer{
+					{Attention: &Attention{KB: &nn.Linear{}, VB: &nn.Linear{}}},
+				},
+			},
+			wantErr: false,
+		},
+		{
+			name: "missing KB",
+			model: &Model{
+				Layers: []Layer{
+					{Attention: &Attention{VB: &nn.Linear{}}},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "missing VB",
+			model: &Model{
+				Layers: []Layer{
+					{Attention: &Attention{KB: &nn.Linear{}}},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "missing both KB and VB",
+			model: &Model{
+				Layers: []Layer{
+					{Attention: &Attention{}},
+				},
+			},
+			wantErr: true,
+		},
+		{
+			name: "nil Attention is ok",
+			model: &Model{
+				Layers: []Layer{
+					{Attention: nil},
+				},
+			},
+			wantErr: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := tt.model.Validate()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Validate() error = %v, wantErr %v", err, tt.wantErr)
+			}
+			if tt.wantErr && err != ErrOldModelFormat {
+				t.Errorf("Validate() error = %v, want %v", err, ErrOldModelFormat)
+			}
+		})
+	}
+}