mlx/benchmarks/python/gather_mm_bench.py
2025-04-17 13:53:11 -07:00

75 lines
2.0 KiB
Python

# Copyright © 2025 Apple Inc.
import mlx.core as mx
from time_utils import time_fn
N = 1024
D = 1024
M = 1024
E = 32
I = 4
def gather_sort(x, indices):
N, M = indices.shape
indices = indices.flatten()
order = mx.argsort(indices)
inv_order = mx.argsort(order)
return x.flatten(0, -3)[order // M], indices[order], inv_order
def scatter_unsort(x, inv_order, shape=None):
x = x[inv_order]
if shape is not None:
x = mx.unflatten(x, 0, shape)
return x
def gather_mm_simulate(x, w, indices):
x, idx, inv_order = gather_sort(x, indices)
for i in range(2):
y = mx.concatenate([x[i] @ w[j].T for i, j in enumerate(idx.tolist())], axis=0)
x = y[:, None]
x = scatter_unsort(x, inv_order, indices.shape)
return x
def time_gather_mm():
x = mx.random.normal((N, 1, 1, D)) / 1024**0.5
w1 = mx.random.normal((E, M, D)) / 1024**0.5
w2 = mx.random.normal((E, D, M)) / 1024**0.5
indices = (mx.random.uniform(shape=(N, I)) * E).astype(mx.uint32)
sorted_indices = mx.sort(indices.flatten()).reshape(N, I)
mx.eval(x, w1, w2, indices, sorted_indices)
def gather_mm(x, w1, w2, indices, sort):
idx = indices
inv_order = None
if sort:
x, idx, inv_order = gather_sort(x, indices)
x = mx.gather_mm(x, w1.swapaxes(-1, -2), rhs_indices=idx, sorted_indices=sort)
x = mx.gather_mm(x, w2.swapaxes(-1, -2), rhs_indices=idx, sorted_indices=sort)
if sort:
x = scatter_unsort(x, inv_order, indices.shape)
return x
time_fn(gather_mm, x, w1, w2, indices, False)
time_fn(gather_mm, x, w1, w2, sorted_indices, False)
time_fn(gather_mm, x, w1, w2, indices, True)
x = mx.random.normal((N * I, D)) / 1024**0.5
w1 = mx.random.normal((M, D)) / 1024**0.5
w2 = mx.random.normal((D, M)) / 1024**0.5
mx.eval(x, w1, w2)
def equivalent_matmul(x, w1, w2):
x = x @ w1.T
x = x @ w2.T
return x
time_fn(equivalent_matmul, x, w1, w2)
if __name__ == "__main__":
time_gather_mm()