RMS norm without scaling (#1915)

This commit is contained in:
Angelos Katharopoulos
2025-02-28 20:26:57 -08:00
committed by GitHub
parent 5d68082881
commit 5e6c130d93
9 changed files with 220 additions and 101 deletions

View File

@@ -10,7 +10,12 @@ def layer_norm(x, w, b, eps):
x = x.astype(mx.float32)
mu = mx.mean(x, -1, keepdims=True)
v = mx.var(x, -1, keepdims=True)
return (x - mu) * mx.rsqrt(v + eps) * w + b
y = (x - mu) * mx.rsqrt(v + eps)
if w is not None:
y = y * w
if b is not None:
y = y + b
return y
def time_layer_norm():
@@ -36,6 +41,28 @@ def time_layer_norm():
time_fn(layer_norm_loop, mx.compile(g1), x, w, b)
time_fn(layer_norm_loop, mx.compile(g2), x, w, b)
f1 = lambda x, y: (layer_norm(x, None, None, 1e-5) * y).sum()
f2 = lambda x, y: (mx.fast.layer_norm(x, None, None, 1e-5) * y).sum()
g1 = mx.grad(f1, argnums=(0,))
g2 = mx.grad(f2, argnums=(0,))
x = mx.random.uniform(shape=(8, 1024, 4096)).astype(mx.float16)
w = mx.random.uniform(shape=(4096,)).astype(mx.float16)
b = mx.random.uniform(shape=(4096,)).astype(mx.float16)
y = mx.random.uniform(shape=(8, 1024, 4096)).astype(mx.float16)
mx.eval(x, w, b, y)
def layer_norm_loop(g, x):
gx = x
for _ in range(32):
gx = g(gx, y)
return gx
time_fn(layer_norm_loop, g1, x)
time_fn(layer_norm_loop, g2, x)
time_fn(layer_norm_loop, mx.compile(g1), x)
time_fn(layer_norm_loop, mx.compile(g2), x)
if __name__ == "__main__":
time_layer_norm()

View File

@@ -9,7 +9,10 @@ def rms_norm(x, w, eps):
ot = x.dtype
x = x.astype(mx.float32)
n = mx.rsqrt(x.square().mean(-1, keepdims=True) + eps)
return (x * n).astype(ot) * w
y = (x * n).astype(ot)
if w is not None:
y = y * w
return y
def time_rms_norm():
@@ -34,6 +37,27 @@ def time_rms_norm():
time_fn(rms_norm_loop, mx.compile(g1), x, w)
time_fn(rms_norm_loop, mx.compile(g2), x, w)
f1 = lambda x, y: (rms_norm(x, None, 1e-5) * y).sum()
f2 = lambda x, y: (mx.fast.rms_norm(x, None, 1e-5) * y).sum()
g1 = mx.grad(f1, argnums=(0,))
g2 = mx.grad(f2, argnums=(0,))
x = mx.random.uniform(shape=(8, 1024, 4096)).astype(mx.float16)
w = mx.random.uniform(shape=(4096,)).astype(mx.float16)
y = mx.random.uniform(shape=(8, 1024, 4096)).astype(mx.float16)
mx.eval(x, w, y)
def rms_norm_loop(g, x):
gx = x
for _ in range(32):
gx = g(gx, y)
return gx
time_fn(rms_norm_loop, g1, x)
time_fn(rms_norm_loop, g2, x)
time_fn(rms_norm_loop, mx.compile(g1), x)
time_fn(rms_norm_loop, mx.compile(g2), x)
if __name__ == "__main__":
time_rms_norm()