cleanups from flash attention branch (#12897)

This commit is contained in:
George Hotz
2025-10-24 14:14:56 +08:00
committed by GitHub
parent 9dac505565
commit 0bde87d8d7
5 changed files with 36 additions and 36 deletions

View File

@@ -42,29 +42,35 @@ elif getenv("BIG") > 0:
else:
BS, HEADS, SEQLEN, EMB = 4, 2, 16, 8
def fa():
Tensor.manual_seed(1337)
with Context(DEBUG=0): q,k,v = [Tensor.rand(BS, HEADS, SEQLEN, EMB).contiguous().realize() for _ in range(3)]
GlobalCounters.reset()
return q.scaled_dot_product_attention(k, v)
def fa_bw():
Tensor.manual_seed(1337)
with Context(DEBUG=0):
q,k,v = [Tensor.rand(BS, HEADS, SEQLEN, EMB).contiguous().realize().requires_grad_() for _ in range(3)]
attn_output = nn.Linear(HEADS*EMB, HEADS*EMB, bias=False)
attn_output.weight.requires_grad_().realize()
target = Tensor.rand(BS, SEQLEN, HEADS*EMB).contiguous().realize()
GlobalCounters.reset()
attn = q.scaled_dot_product_attention(k, v).contiguous().contiguous_backward()
attn = attn.transpose(1, 2).reshape(BS, SEQLEN, -1)
out = attn_output(attn)
loss = (out - target).square().mean()
loss.backward()
#ret = [out, Tensor.stack(q.grad, k.grad, v.grad, dim=-1)]
#ret = [out, Tensor.stack(q.grad, k.grad, dim=-1), v.grad]
ret = [out, q.grad, k.grad, v.grad]
Tensor.realize(*ret)
return ret
@unittest.skipIf(isinstance(Device[Device.DEFAULT].renderer, (NIRRenderer, PTXRenderer)), "broken in LVP and PTX")
class TestPcontig(unittest.TestCase):
def test_flash_attention_bw(self):
def fa_bw():
Tensor.manual_seed(1337)
with Context(DEBUG=0):
q,k,v = [Tensor.rand(BS, HEADS, SEQLEN, EMB).contiguous().realize().requires_grad_() for _ in range(3)]
attn_output = nn.Linear(HEADS*EMB, HEADS*EMB, bias=False)
attn_output.weight.requires_grad_().realize()
target = Tensor.rand(BS, SEQLEN, HEADS*EMB).contiguous().realize()
GlobalCounters.reset()
attn = q.scaled_dot_product_attention(k, v).contiguous().contiguous_backward()
attn = attn.transpose(1, 2).reshape(BS, SEQLEN, -1)
out = attn_output(attn)
loss = (out - target).square().mean()
loss.backward()
#ret = [out, Tensor.stack(q.grad, k.grad, v.grad, dim=-1)]
#ret = [out, Tensor.stack(q.grad, k.grad, dim=-1), v.grad]
ret = [out, q.grad, k.grad, v.grad]
Tensor.realize(*ret)
return ret
with Context(PCONTIG=max(2, PCONTIG.value), DEBUG=2):
grads = fa_bw()
print(f"{GlobalCounters.global_ops/1e9:.2f} GFLOPS")
@@ -80,17 +86,11 @@ class TestPcontig(unittest.TestCase):
self.assertLessEqual(mse, 1e-6)
def test_flash_attention(self):
def fa():
Tensor.manual_seed(1337)
with Context(DEBUG=0): q,k,v = [Tensor.rand(BS, HEADS, SEQLEN, EMB).contiguous().realize() for _ in range(3)]
GlobalCounters.reset()
return q.scaled_dot_product_attention(k, v).realize()
with Context(PCONTIG=2, DEBUG=2):
ret = fa()
ret = fa().realize()
print(f"{GlobalCounters.global_ops/1e9:.2f} GFLOPS")
with Context(DEBUG=2):
cmp = fa()
cmp = fa().realize()
print(f"{GlobalCounters.global_ops/1e9:.2f} GFLOPS")
with Context(DEBUG=0):
mse = ((cmp-ret)**2).sum().item()