import mlx.core as mx import numpy as np from mlx.utils import tree_map from time_utils import time_fn L = 65536 H = 32 H_k = 32 // 4 D = 128 def attention(q, k, v): B, Hq, L, D = q.shape _, Hk, S, _ = k.shape q = q.reshape(B, Hk, Hq // Hk, L, D) k = k[:, :, None, :, :] v = v[:, :, None, :, :] s = q @ k.transpose(0, 1, 2, 4, 3) p = mx.softmax(s.astype(mx.float32), axis=-1).astype(s.dtype) o = p @ v return o.reshape(B, Hq, L, D) def sdpa(q, k, v): return mx.fast.scaled_dot_product_attention(q, k, v, scale=1.0, mask=None) def quant_sdpa(q, k, v): return mx.fast.quantized_scaled_dot_product_attention( q, *k, *v, scale=1.0, mask=None, bits=8 ) def quant_attention(q, k, v): B, Hq, L, D = q.shape Hk = k[0].shape[1] q = q.reshape((B, Hk, Hq // Hk, L, D)) k = tree_map(lambda x: mx.expand_dims(x, axis=2), k) v = tree_map(lambda x: mx.expand_dims(x, axis=2), v) scores = mx.quantized_matmul(q, *k, transpose=True) scores = mx.softmax(scores, axis=-1) out = mx.quantized_matmul(scores, *v, transpose=False) out = out.reshape((B, Hq, L, D)) return out def time_self_attention_primitives(q, k, v): time_fn(attention, q, k, v) def time_self_attention_sdpa(q, k, v): time_fn(sdpa, q, k, v) def time_self_attention_quant_sdpa(q, k, v): time_fn(quant_sdpa, q, k, v) def time_self_attention_quant_primitives(q, k, v): time_fn(quant_attention, q, k, v) if __name__ == "__main__": mx.random.seed(3) q = mx.random.uniform(shape=(1, H, 1, D)) k = mx.random.uniform(shape=(1, H_k, L, D)) v = mx.random.uniform(shape=(1, H_k, L, D)) mx.eval(q, k, v) k_quant = mx.quantize(k) v_quant = mx.quantize(v) mx.eval(k_quant, v_quant) time_self_attention_sdpa(q, k, v) time_self_attention_quant_sdpa(q, k_quant, v_quant) time_self_attention_primitives(q, k, v) time_self_attention_quant_primitives(q, k_quant, v_quant)