Module: SmolLM2KVMetal

Defined in:
lib/toy/llm/engine/llama_kv_engine_metal.rb

Class Method Summary collapse

Class Method Details

.decode_step(kv_cache, token_id, pos) ⇒ Object

Decode one new token at position ‘pos`. Returns the (1, vocab) logits Mat for the new position. If `kv_cache.trace_on` is set the rebuild path inserts taps and we dump stats before reading logits.



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# File 'lib/toy/llm/engine/llama_kv_engine_metal.rb', line 1516

def self.decode_step(kv_cache, token_id, pos)
  TinyNNMetal.tnn_reset_for_rebuild(kv_cache.sess)
  step = kv_cache.build_decode_step(pos)
  TinyNNMetal.tnn_realize(kv_cache.sess, step.kv_step_logits)
  TinyNNMetal.upload_int_array(kv_cache.sess, step.t_token_id, [token_id])
  TinyNNMetal.upload_int_array(kv_cache.sess, step.t_pos,      [pos])
  TinyNNMetal.tnn_compute(kv_cache.sess)
  kv_cache.dump_trace
  TinyNNMetal.download_row_major(kv_cache.sess, step.kv_step_logits, 1, kv_cache.vocab_size)
end

.upload_from(kv_cache, model) ⇒ Object

Upload all Toy::SmolLM2 weights into a realized cache (+ zero-init the K/V buffers).



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# File 'lib/toy/llm/engine/llama_kv_engine_metal.rb', line 1449

def self.upload_from(kv_cache, model)
  sess     = kv_cache.sess
  n        = kv_cache.n_layers
  n_heads  = kv_cache.n_heads
  n_kv     = kv_cache.n_kv
  d_model  = kv_cache.d_model
  d_head   = kv_cache.d_head
  max_T    = kv_cache.max_T

  TinyNNMetal.upload_row_major(sess, kv_cache.t_token_embed, model.token_embed.weight)
  TinyNNMetal.tnn_upload_from_float_array(sess, kv_cache.t_final_norm_gamma,
                                      model.final_norm.gamma, d_model)
  if kv_cache.has_untied_output
    TinyNNMetal.upload_row_major(sess, kv_cache.t_output, model.output_proj)
  end

  # P5.2: K and V share the same layout ne=[d_head, max_T] now,
  # so they share the same zero-init Mat.
  kv_zero = Mat.new(max_T, d_head)

  li = 0
  while li < n
    blk_n = model.stack[li]
    blk_f = kv_cache.kv_blocks_ffi[li]

    TinyNNMetal.tnn_upload_from_float_array(sess, blk_f.t_rn1_gamma, blk_n.rn1.gamma, d_model)
    TinyNNMetal.tnn_upload_from_float_array(sess, blk_f.t_rn2_gamma, blk_n.rn2.gamma, d_model)

    hq = 0
    while hq < n_heads
      TinyNNMetal.stage_transposed_and_upload(sess, blk_f.t_w_q[hq], blk_n.attn.w_q[hq])
      if kv_cache.has_qkv_bias
        TinyNNMetal.tnn_upload_from_float_array(sess, blk_f.t_b_q[hq], blk_n.attn.b_q[hq], d_head)
      end
      hq = hq + 1
    end

    hkv = 0
    while hkv < n_kv
      TinyNNMetal.stage_transposed_and_upload(sess, blk_f.t_w_k[hkv], blk_n.attn.w_k[hkv])
      TinyNNMetal.stage_transposed_and_upload(sess, blk_f.t_w_v[hkv], blk_n.attn.w_v[hkv])
      if kv_cache.has_qkv_bias
        TinyNNMetal.tnn_upload_from_float_array(sess, blk_f.t_b_k[hkv], blk_n.attn.b_k[hkv], d_head)
        TinyNNMetal.tnn_upload_from_float_array(sess, blk_f.t_b_v[hkv], blk_n.attn.b_v[hkv], d_head)
      end
      # P5.1+P5.2: same Q8 skip rule as realize_for_mmap.
      if kv_cache.kv_type_k != 8
        TinyNNMetal.upload_row_major(sess, blk_f.t_K[hkv], kv_zero)
      end
      if kv_cache.kv_type_v != 8
        TinyNNMetal.upload_row_major(sess, blk_f.t_V[hkv], kv_zero)
      end
      hkv = hkv + 1
    end

    TinyNNMetal.stage_transposed_and_upload(sess, blk_f.t_w_o,    blk_n.attn.w_o)
    TinyNNMetal.stage_transposed_and_upload(sess, blk_f.t_w_gate, blk_n.ffn.w_gate)
    TinyNNMetal.stage_transposed_and_upload(sess, blk_f.t_w_up,   blk_n.ffn.w_up)
    TinyNNMetal.stage_transposed_and_upload(sess, blk_f.t_w_down, blk_n.ffn.w_down)

    li = li + 1
  end
end