model: add llama3 architecture to mlxrunner (#14277)

This commit is contained in:
Patrick Devine
2026-02-15 23:06:28 -08:00
committed by GitHub
parent 041fb77639
commit 9b795698b8
2 changed files with 324 additions and 0 deletions

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@@ -5,4 +5,5 @@ package mlxrunner
import (
_ "github.com/ollama/ollama/x/models/gemma3"
_ "github.com/ollama/ollama/x/models/glm4_moe_lite"
_ "github.com/ollama/ollama/x/models/llama"
)

323
x/models/llama/llama.go Normal file
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@@ -0,0 +1,323 @@
//go:build mlx
// Package llama provides a Llama-style decoder-only transformer for MLX.
package llama
import (
"encoding/json"
"fmt"
"math"
"github.com/ollama/ollama/x/imagegen/tokenizer"
"github.com/ollama/ollama/x/mlxrunner/cache"
"github.com/ollama/ollama/x/mlxrunner/mlx"
"github.com/ollama/ollama/x/mlxrunner/model"
"github.com/ollama/ollama/x/mlxrunner/model/base"
"github.com/ollama/ollama/x/models/nn"
)
func init() {
base.Register("LlamaForCausalLM", newModel)
}
// Config holds Llama model configuration.
type Config struct {
HiddenSize int32 `json:"hidden_size"`
NumHiddenLayers int32 `json:"num_hidden_layers"`
IntermediateSize int32 `json:"intermediate_size"`
NumAttentionHeads int32 `json:"num_attention_heads"`
NumKeyValueHeads int32 `json:"num_key_value_heads"`
VocabSize int32 `json:"vocab_size"`
RMSNormEps float32 `json:"rms_norm_eps"`
RopeTheta float32 `json:"rope_theta"`
MaxPositionEmbeddings int32 `json:"max_position_embeddings"`
TieWordEmbeddings bool `json:"tie_word_embeddings"`
// Quantization parameters (set during load based on model quantization).
QuantGroupSize int `json:"-"`
QuantBits int `json:"-"`
QuantMode string `json:"-"`
TensorQuant map[string]*model.TensorQuantInfo `json:"-"`
// Computed fields.
HeadDim int32 `json:"-"`
Scale float32 `json:"-"`
}
// Model is a Llama text model.
type Model struct {
EmbedTokens *nn.Embedding
Layers []*Layer
Norm *nn.RMSNorm
LMHead nn.LinearLayer
tok *tokenizer.Tokenizer
*Config
weightPrefix string
}
type Layer struct {
Attention *Attention
MLP *MLP
AttentionNorm *nn.RMSNorm
MLPNorm *nn.RMSNorm
}
type Attention struct {
QProj nn.LinearLayer
KProj nn.LinearLayer
VProj nn.LinearLayer
OProj nn.LinearLayer
}
type MLP struct {
GateProj nn.LinearLayer
UpProj nn.LinearLayer
DownProj nn.LinearLayer
}
func resolveWeightPrefix(tensors map[string]*mlx.Array) string {
for _, prefix := range []string{"", "language_model."} {
if tensors[prefix+"model.embed_tokens.weight"] != nil {
return prefix
}
}
return ""
}
func newModel(root *model.Root) (base.Model, error) {
configData, err := root.Manifest.ReadConfig("config.json")
if err != nil {
return nil, fmt.Errorf("load config: %w", err)
}
var cfg Config
if err := json.Unmarshal(configData, &cfg); err != nil {
return nil, fmt.Errorf("parse config: %w", err)
}
if cfg.HiddenSize <= 0 {
return nil, fmt.Errorf("invalid hidden_size: %d", cfg.HiddenSize)
}
if cfg.NumAttentionHeads <= 0 {
return nil, fmt.Errorf("invalid num_attention_heads: %d", cfg.NumAttentionHeads)
}
if cfg.NumKeyValueHeads <= 0 {
cfg.NumKeyValueHeads = cfg.NumAttentionHeads
}
if cfg.HiddenSize%cfg.NumAttentionHeads != 0 {
return nil, fmt.Errorf("hidden_size (%d) must be divisible by num_attention_heads (%d)", cfg.HiddenSize, cfg.NumAttentionHeads)
}
if cfg.HeadDim == 0 {
cfg.HeadDim = cfg.HiddenSize / cfg.NumAttentionHeads
}
if cfg.HeadDim <= 0 {
return nil, fmt.Errorf("invalid head_dim: %d", cfg.HeadDim)
}
if cfg.NumAttentionHeads%cfg.NumKeyValueHeads != 0 {
return nil, fmt.Errorf("num_attention_heads (%d) must be divisible by num_key_value_heads (%d)", cfg.NumAttentionHeads, cfg.NumKeyValueHeads)
}
if cfg.RopeTheta == 0 {
cfg.RopeTheta = 10000
}
if cfg.RMSNormEps == 0 {
cfg.RMSNormEps = 1e-5
}
cfg.Scale = float32(1.0 / math.Sqrt(float64(cfg.HeadDim)))
if qt := root.QuantType(); qt != "" {
cfg.QuantGroupSize, cfg.QuantBits, cfg.QuantMode = model.QuantizationParams(qt)
if gs := root.GroupSize(); gs > 0 {
cfg.QuantGroupSize = gs
}
} else {
cfg.QuantGroupSize, cfg.QuantBits, cfg.QuantMode = model.QuantizationParams("")
}
cfg.TensorQuant = root.AllTensorQuant()
tokData, err := root.Manifest.ReadConfig("tokenizer.json")
if err != nil {
return nil, fmt.Errorf("load tokenizer config: %w", err)
}
tokConfig := &tokenizer.TokenizerConfig{
ConfigJSON: configData,
}
if genConfigData, err := root.Manifest.ReadConfig("generation_config.json"); err == nil {
tokConfig.GenerationConfigJSON = genConfigData
}
if tokConfigData, err := root.Manifest.ReadConfig("tokenizer_config.json"); err == nil {
tokConfig.TokenizerConfigJSON = tokConfigData
}
tok, err := tokenizer.LoadFromBytesWithConfig(tokData, tokConfig)
if err != nil {
return nil, fmt.Errorf("parse tokenizer: %w", err)
}
m := &Model{
Layers: make([]*Layer, cfg.NumHiddenLayers),
Config: &cfg,
tok: tok,
}
return m, nil
}
// LoadWeights receives all tensors loaded from the manifest and assigns them
// to model fields.
func (m *Model) LoadWeights(tensors map[string]*mlx.Array) error {
m.weightPrefix = resolveWeightPrefix(tensors)
prefix := m.weightPrefix
linears := model.NewLinearFactory(tensors, m.QuantGroupSize, m.QuantBits, m.QuantMode, m.TensorQuant)
embedWeight := tensors[prefix+"model.embed_tokens.weight"]
if embedWeight == nil {
return fmt.Errorf("missing embedding weight: %smodel.embed_tokens.weight", prefix)
}
m.EmbedTokens = nn.NewEmbedding(embedWeight)
normWeight := tensors[prefix+"model.norm.weight"]
if normWeight == nil {
return fmt.Errorf("missing final norm weight: %smodel.norm.weight", prefix)
}
m.Norm = nn.NewRMSNorm(normWeight, m.RMSNormEps)
if m.TieWordEmbeddings {
m.LMHead = nn.NewLinear(embedWeight, nil)
} else if lmHead := linears.Make(prefix + "lm_head"); lmHead != nil {
m.LMHead = lmHead
} else if lmHead := linears.Make("lm_head"); lmHead != nil {
m.LMHead = lmHead
} else {
// Fallback used by many Llama checkpoints where output is tied.
m.LMHead = nn.NewLinear(embedWeight, nil)
}
for i := int32(0); i < m.NumHiddenLayers; i++ {
layerPrefix := fmt.Sprintf("%smodel.layers.%d", prefix, i)
layer := &Layer{
Attention: &Attention{},
MLP: &MLP{},
}
if w := tensors[layerPrefix+".input_layernorm.weight"]; w != nil {
layer.AttentionNorm = nn.NewRMSNorm(w, m.RMSNormEps)
}
if w := tensors[layerPrefix+".post_attention_layernorm.weight"]; w != nil {
layer.MLPNorm = nn.NewRMSNorm(w, m.RMSNormEps)
}
layer.Attention.QProj = linears.Make(layerPrefix + ".self_attn.q_proj")
layer.Attention.KProj = linears.Make(layerPrefix + ".self_attn.k_proj")
layer.Attention.VProj = linears.Make(layerPrefix + ".self_attn.v_proj")
layer.Attention.OProj = linears.Make(layerPrefix + ".self_attn.o_proj")
layer.MLP.GateProj = linears.Make(layerPrefix + ".mlp.gate_proj")
layer.MLP.UpProj = linears.Make(layerPrefix + ".mlp.up_proj")
layer.MLP.DownProj = linears.Make(layerPrefix + ".mlp.down_proj")
if layer.AttentionNorm == nil {
return fmt.Errorf("layer %d: missing input_layernorm", i)
}
if layer.MLPNorm == nil {
return fmt.Errorf("layer %d: missing post_attention_layernorm", i)
}
if layer.Attention.QProj == nil || layer.Attention.KProj == nil || layer.Attention.VProj == nil || layer.Attention.OProj == nil {
return fmt.Errorf("layer %d: missing attention projections", i)
}
if layer.MLP.GateProj == nil || layer.MLP.UpProj == nil || layer.MLP.DownProj == nil {
return fmt.Errorf("layer %d: missing mlp projections", i)
}
m.Layers[i] = layer
}
collected := mlx.Collect(m)
mlx.Eval(collected...)
return nil
}
func (m *Model) Forward(tokens *mlx.Array, caches []cache.Cache) *mlx.Array {
dims := tokens.Dims()
B, L := int32(dims[0]), int32(dims[1])
h := m.EmbedTokens.Forward(tokens)
for i, layer := range m.Layers {
var c cache.Cache
if caches != nil && i < len(caches) {
c = caches[i]
}
h = layer.Forward(h, c, B, L, m.Config)
}
return m.Norm.Forward(h, m.RMSNormEps)
}
func (m *Model) Unembed(x *mlx.Array) *mlx.Array {
return m.LMHead.Forward(x)
}
func (m *Model) NumLayers() int {
return len(m.Layers)
}
func (m *Model) Tokenizer() *tokenizer.Tokenizer {
return m.tok
}
func (m *Model) NewCaches() []cache.Cache {
caches := make([]cache.Cache, len(m.Layers))
for i := range caches {
caches[i] = cache.NewKVCache()
}
return caches
}
func (l *Layer) Forward(x *mlx.Array, c cache.Cache, B, L int32, cfg *Config) *mlx.Array {
h := mlx.Add(x, l.Attention.Forward(l.AttentionNorm.Forward(x, cfg.RMSNormEps), c, B, L, cfg))
return mlx.Add(h, l.MLP.Forward(l.MLPNorm.Forward(h, cfg.RMSNormEps)))
}
func (a *Attention) Forward(x *mlx.Array, c cache.Cache, B, L int32, cfg *Config) *mlx.Array {
q := a.QProj.Forward(x)
k := a.KProj.Forward(x)
v := a.VProj.Forward(x)
q = mlx.Reshape(q, B, L, cfg.NumAttentionHeads, cfg.HeadDim)
q = mlx.Transpose(q, 0, 2, 1, 3)
k = mlx.Reshape(k, B, L, cfg.NumKeyValueHeads, cfg.HeadDim)
k = mlx.Transpose(k, 0, 2, 1, 3)
v = mlx.Reshape(v, B, L, cfg.NumKeyValueHeads, cfg.HeadDim)
v = mlx.Transpose(v, 0, 2, 1, 3)
offset := 0
if c != nil {
offset = c.Offset()
}
q = mlx.RoPEWithBase(q, int(cfg.HeadDim), false, cfg.RopeTheta, 1.0, offset)
k = mlx.RoPEWithBase(k, int(cfg.HeadDim), false, cfg.RopeTheta, 1.0, offset)
if c != nil {
k, v = c.Update(k, v)
}
repeatFactor := cfg.NumAttentionHeads / cfg.NumKeyValueHeads
if repeatFactor > 1 {
k = nn.RepeatKV(k, repeatFactor)
v = nn.RepeatKV(v, repeatFactor)
}
out := mlx.ScaledDotProductAttentionCausal(q, k, v, cfg.Scale, L > 1)
out = mlx.Reshape(mlx.Transpose(out, 0, 2, 1, 3), B, L, cfg.NumAttentionHeads*cfg.HeadDim)
return a.OProj.Forward(out)
}
func (m *MLP) Forward(x *mlx.Array) *mlx.Array {
return m.DownProj.Forward(mlx.Mul(mlx.SiLU(m.GateProj.Forward(x)), m.UpProj.Forward(x)))
}