pytorch/test/dynamo/test_hooks.py
voznesenskym 3e4d14702a On grad access, check if grad has changed and update stored example grad as needed (#112811)
Fixes https://github.com/pytorch/pytorch/issues/112446

This is a doozy of a PR, there's a few important things to keep in mind here:

1) We MUST lift all tensors accessed via attrs to inputs, getattr is a no go in the graph, it violates the aot_autograd contract. Furthermore, aot_autograd does not know how to apply in-place ops to intermediary tensors that are attributes (aka from getattr) anyway. Views from ops are fine.

2) `.grad` access handling in dynamo peeks at the underlying value, the real tensor, because re-piping FakeTensors already made with this fake_mode through builder anew is a no go.

3) We have no proper mechanism for updating the hint / grapharg.example (the real value in (2) above) midway through trace

Therefore, what we need to do is reconcile the difference in grad stashed on grapharg.example. The easiest way to do this is lazily, upon .grad access, by reading the new value off the right fake tensors. We can then make a tensor using that data as a hint to VariableBuilder to make the right VariableTracker. Note that the example value used here (torch.zeros) in the PR, is a dummy value only used as a tracing hint, it does not leak out into real runtime code.

Alternatively, we could implement accumulate_grad_ in python...

Pull Request resolved: https://github.com/pytorch/pytorch/pull/112811
Approved by: https://github.com/jansel
2023-11-08 05:45:00 +00:00

612 lines
21 KiB
Python

# Owner(s): ["module: dynamo"]
import contextlib
import functools
import torch
import torch._dynamo
import torch._dynamo.test_case
import torch._dynamo.testing
from functorch.compile import nop
from torch._dynamo import compiled_autograd
from torch._functorch.aot_autograd import aot_module_simplified
def compiler_fn(gm):
return torch._dynamo.optimize("inductor", nopython=True, dynamic=True)(gm)
def global_hook_0(grad):
return grad * 4
def global_hook_1(grad):
return grad / 2
def global_hook_2(grad):
return grad * 3
h0 = None
class HooksTests(torch._dynamo.test_case.TestCase):
def test_tensor_only_register_hook_in_graph_lambda(self):
def fn(x):
x.register_hook(lambda grad: grad * 2)
return x
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v = fn(v)
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([2.0, 4.0, 6.0]))
self.assertEqual(cnts.frame_count, 0)
def test_tensor_register_hook_in_graph_lambda(self):
def fn(x, y, z):
x.register_hook(lambda grad: grad * 2)
return x, y * y, z * z
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v = fn(v, torch.randn([2, 2]), torch.randn([2, 2]))[0]
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([2.0, 4.0, 6.0]))
self.assertEqual(cnts.frame_count, 1)
def test_tensor_register_hook_in_graph_break_handle_lambda(self):
def fn(x, y, z):
handle = x.register_hook(lambda grad: grad * 2)
z = z * z
handle.remove()
x.register_hook(lambda grad: grad * 3)
return x, y * y, z
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v = fn(v, torch.randn([2, 2]), torch.randn([2, 2]))[0]
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([3.0, 6.0, 9.0]))
self.assertEqual(cnts.frame_count, 2)
def test_tensor_register_hook_multi_handle_return(self):
def fn(x, y, z):
handle = x.register_hook(lambda grad: grad * 2)
h2 = handle
z = z * z
return x, y * y, z, handle, h2
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v, y, z, h, h2 = fn(v, torch.randn([2, 2]), torch.randn([2, 2]))
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([2.0, 4.0, 6.0]))
self.assertEqual(cnts.frame_count, 1)
self.assertNotEqual(h, None)
self.assertNotEqual(h2, None)
self.assertEqual(h2, h)
def test_tensor_register_hook_repeated_handle_return(self):
def fn(x, y, z):
handle = x.register_hook(lambda grad: grad * 2)
h2 = handle
z = z * z
return x, y * y, z, handle, handle
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v, y, z, h, h2 = fn(v, torch.randn([2, 2]), torch.randn([2, 2]))
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([2.0, 4.0, 6.0]))
self.assertEqual(cnts.frame_count, 1)
self.assertNotEqual(h, None)
self.assertNotEqual(h2, None)
self.assertEqual(h2, h)
def test_tensor_register_hook_repeated_handle_not_local(self):
def fn(x, y, z, mod):
mod.handle = x.register_hook(lambda grad: grad * 2)
z = z * z
return x, y * y, z
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
mod = torch.nn.Module()
mod.handle = None
v, y, z = fn(v, torch.randn([2, 2]), torch.randn([2, 2]), mod)
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([2.0, 4.0, 6.0]))
self.assertEqual(cnts.frame_count, 1)
self.assertNotEqual(mod.handle, None)
def test_tensor_only_register_hook_in_graph_local(self):
def local_hook(grad):
return grad * 2
def fn(x):
x.register_hook(local_hook)
return x
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v = fn(v)
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([2.0, 4.0, 6.0]))
self.assertEqual(cnts.frame_count, 0)
def test_tensor_only_register_hook_in_graph_local_inner(self):
def fn(x):
def local_hook(grad):
return grad * 2
z = x * x
x.register_hook(local_hook)
z.register_hook(local_hook)
return x, z
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v = fn(v)
v[0].backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v[0].grad, torch.tensor([2.0, 4.0, 6.0]))
self.assertEqual(cnts.frame_count, 1)
def test_tensor_register_hook_in_graph_local(self):
def local_hook(grad):
return grad * 2
def fn(x, y, z):
x.register_hook(local_hook)
return x, y * y, z * z
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v = fn(v, torch.randn([2, 2]), torch.randn([2, 2]))[0]
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([2.0, 4.0, 6.0]))
self.assertEqual(cnts.frame_count, 1)
def test_tensor_register_hook_in_graph_break_handle_local(self):
def local_hook(grad):
return grad * 2
def local_hook2(grad):
return grad * 3
def fn(x, y, z):
handle = x.register_hook(local_hook)
z = z * z
handle.remove()
x.register_hook(local_hook2)
return x, y * y, z
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v = fn(v, torch.randn([2, 2]), torch.randn([2, 2]))[0]
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([3.0, 6.0, 9.0]))
def test_tensor_register_global_hook(self):
def fn(x):
x.register_hook(global_hook_0)
return x, x * x
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v = fn(v)[0]
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([4.0, 8.0, 12.0]))
self.assertEqual(cnts.frame_count, 1)
def test_tensor_register_multiple_hooks(self):
def fn(x):
x.register_hook(global_hook_0) # * 4
x.register_hook(global_hook_1) # / 2
x.register_hook(global_hook_2) # * 3
return x, x * x
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v = fn(v)[0]
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([6.0, 12.0, 18.0]))
self.assertEqual(cnts.frame_count, 1)
def test_tensor_register_multiple_hooks_handles_in_list(self):
def fn(x):
h0 = x.register_hook(global_hook_0) # * 4
h1 = x.register_hook(global_hook_1) # / 2
h2 = x.register_hook(global_hook_2) # * 3
return x, x * x, h0, h1, h2
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v, r, handle_0, handle_1, handle_2 = fn(v)
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([6.0, 12.0, 18.0]))
handle_0.remove()
handle_1.remove()
handle_2.remove()
v.backward(torch.tensor([1.0, 2.0, 3.0]))
# Handles gone, grad is just applied as is
self.assertEqual(v.grad, torch.tensor([7.0, 14.0, 21.0]))
self.assertEqual(cnts.frame_count, 1)
def test_tensor_register_global_hooks_handles_in_list(self):
def fn(x):
global h0
h0 = x.register_hook(global_hook_0) # * 4
return x, x * x
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts)(fn)
v = torch.tensor([0.0, 0.0, 0.0], requires_grad=True)
v, r = fn(v)
self.assertIsNotNone(h0)
v.backward(torch.tensor([1.0, 2.0, 3.0]))
self.assertEqual(v.grad, torch.tensor([4.0, 8.0, 12.0]))
h0.remove()
v.backward(torch.tensor([1.0, 2.0, 3.0]))
# Handles gone, grad is just applied as is
self.assertEqual(v.grad, torch.tensor([5.0, 10.0, 15.0]))
# NYI!
self.assertEqual(cnts.frame_count, 0)
def test_intermediary_hooks(self):
# Graph breaks because compiled_autograd is not set
def simple_hook(g):
return g * 2
def f(x):
y = x + 1
y.register_hook(simple_hook)
z = y + 1
return z
out = torch.randn(1, requires_grad=True)
cnts = torch._dynamo.testing.CompileCounter()
fn = torch._dynamo.optimize(cnts, nopython=False)(f)
res = fn(out)
res.backward()
self.assertEqual(res, f(out))
self.assertEqual(cnts.frame_count, 2)
self.assertEqual(out.grad, torch.Tensor([2.0]))
def test_intermediary_hooks_same_on_aot_eager(self):
def my_hook(grad, *, k=0):
return grad + k
class MyMod(torch.nn.Module):
def forward(self, x):
y = x.mul(2)
hook1 = functools.partial(my_hook, k=3)
hook2 = functools.partial(my_hook, k=4)
y.register_hook(hook1)
y.register_hook(hook2)
z = y.mul(3)
return (z,)
mod = MyMod()
x0 = torch.ones(4, requires_grad=True)
eager_out = mod(x0)
eager_out[0].backward(torch.ones(4))
x1 = torch.ones(4, requires_grad=True)
mod_compiled = aot_module_simplified(mod, (x1,), nop)
aot_out = mod_compiled(x1)
aot_out[0].backward(torch.ones(4))
x2 = torch.ones(4, requires_grad=True)
with compiled_autograd.enable(compiler_fn):
dynamo_out = torch._dynamo.optimize("aot_eager", nopython=True)(mod)(x2)
dynamo_out[0].backward(torch.ones(4))
self.assertEqual(dynamo_out, aot_out)
self.assertEqual(dynamo_out, eager_out)
self.assertEqual(x0.grad, x1.grad)
self.assertEqual(x0.grad, x2.grad)
def test_input_hooks_same(self):
backends = ["eager", "aot_eager", "inductor"]
for backend in backends:
def my_hook(grad, *, k=0):
return grad + k
hook = functools.partial(my_hook, k=3)
class MyMod(torch.nn.Module):
def forward(self, x):
x.register_hook(hook)
y = x.mul(2)
z = y.mul(3)
return (z,)
mod = MyMod()
x0 = torch.ones(4, requires_grad=True)
eager_out = mod(x0)
eager_out[0].backward(torch.ones(4))
x1 = torch.ones(4, requires_grad=True)
mod_compiled = aot_module_simplified(mod, (x1,), nop)
aot_out = mod_compiled(x1)
aot_out[0].backward(torch.ones(4))
x2 = torch.ones(4, requires_grad=True)
dynamo_out = torch._dynamo.optimize(backend, nopython=True)(mod)(x2)
with compiled_autograd.enable(compiler_fn):
dynamo_out[0].backward(torch.ones(4))
self.assertEqual(dynamo_out, aot_out)
self.assertEqual(dynamo_out, eager_out)
self.assertEqual(x0.grad, x1.grad)
self.assertEqual(x0.grad, x2.grad)
def test_intermediary_hooks_same_on_inductor(self):
def my_hook(grad, *, k=0):
return grad + k
class MyMod(torch.nn.Module):
def forward(self, x):
y = x.mul(2)
hook1 = functools.partial(my_hook, k=3)
hook2 = functools.partial(my_hook, k=4)
y.register_hook(hook1)
y.register_hook(hook2)
z = y.mul(3)
return (z,)
mod = MyMod()
x0 = torch.ones(4, requires_grad=True)
eager_out = mod(x0)
eager_out[0].backward(torch.ones(4))
x1 = torch.ones(4, requires_grad=True)
mod_compiled = aot_module_simplified(mod, (x1,), nop)
aot_out = mod_compiled(x1)
aot_out[0].backward(torch.ones(4))
x2 = torch.ones(4, requires_grad=True)
with compiled_autograd.enable(compiler_fn):
dynamo_out = torch._dynamo.optimize("inductor", nopython=True)(mod)(x2)
dynamo_out[0].backward(torch.ones(4))
self.assertEqual(dynamo_out, aot_out)
self.assertEqual(dynamo_out, eager_out)
self.assertEqual(x0.grad, x1.grad)
self.assertEqual(x0.grad, x2.grad)
def test_complex_state_mutation_in_intermediary_hooks_same_on_inductor(self):
class SomePyClass:
count = 0
def do_stuff(self, grad):
if self.count % 2 == 0:
r = grad * grad
else:
r = grad + grad
self.count += 1
return r
def complex_state_touching_hook(grad, *, obj):
return obj.do_stuff(grad)
class MyMod(torch.nn.Module):
def forward(self, x, obj):
y = x.mul(2)
hook1 = functools.partial(complex_state_touching_hook, obj=obj)
hook2 = functools.partial(complex_state_touching_hook, obj=obj)
y.register_hook(hook1)
y.register_hook(hook2)
z = y.mul(3)
return (z,)
mod = MyMod()
obj = SomePyClass()
x0 = torch.ones(4, requires_grad=True)
eager_out = mod(x0, obj)
eager_out[0].backward(torch.ones(4))
# Eager 2
self.assertEqual(obj.count, 2)
x2 = torch.ones(4, requires_grad=True)
with compiled_autograd.enable(compiler_fn):
dynamo_out = torch._dynamo.optimize("inductor", nopython=True)(mod)(x2, obj)
dynamo_out[0].backward(torch.ones(4))
self.assertEqual(dynamo_out, eager_out)
# Eager 2 + compiled 2
self.assertEqual(obj.count, 4)
self.assertEqual(x0.grad, x2.grad)
def test_complex_state_mutation_in_intermediary_hooks_same_on_inductor_with_graph_break(
self,
):
class SomePyClass:
grad_as_str = "None"
count = 0
def write_grad_as_str_and_do_stuff(self, grad):
self.grad_as_str = str(grad)
if self.count % 2 == 0:
r = grad * grad
else:
r = grad + grad
print("Break!")
self.count += 1
return r
def complex_state_touching_hook(grad, *, obj):
return obj.write_grad_as_str_and_do_stuff(grad)
class MyMod(torch.nn.Module):
def forward(self, x, obj):
y = x.mul(2)
hook1 = functools.partial(complex_state_touching_hook, obj=obj)
hook2 = functools.partial(complex_state_touching_hook, obj=obj)
y.register_hook(hook1)
y.register_hook(hook2)
z = y.mul(3)
return (z,)
mod = MyMod()
obj = SomePyClass()
x0 = torch.ones(4, requires_grad=True)
eager_out = mod(x0, obj)
eager_out[0].backward(torch.ones(4))
x2 = torch.ones(4, requires_grad=True)
with compiled_autograd.enable(compiler_fn):
dynamo_out = torch._dynamo.optimize("inductor", nopython=True)(mod)(x2, obj)
with self.assertRaisesRegex(
torch._dynamo.exc.Unsupported, ".*BuiltinVariable\\(str\\).*"
):
dynamo_out[0].backward(torch.ones(4))
self.assertEqual(obj.count, 2)
def test_no_recompile_on_hook_identity_change(self):
def my_hook(grad, k=0):
return grad + k
def my_hook2(grad):
return grad * 2
class MyMod(torch.nn.Module):
def forward(self, x):
y = x.mul(2)
y.register_hook(my_hook)
y.register_hook(my_hook)
z = y.mul(3)
return (z,)
mod = MyMod()
x0 = torch.ones(4, requires_grad=True)
eager_out = mod(x0)
eager_out[0].backward(torch.ones(4))
x1 = torch.ones(4, requires_grad=True)
with compiled_autograd.enable(compiler_fn):
cnts = torch._dynamo.testing.CompileCounterWithBackend("aot_eager")
comp_mod = torch._dynamo.optimize(cnts, nopython=True)(mod)
comp_out = comp_mod(x1)
comp_out[0].backward(torch.ones(4))
self.assertEqual(cnts.frame_count, 1)
my_hook = my_hook2 # noqa: F811
self.assertEqual(x0.grad, x1.grad)
eager_out = mod(x0)
eager_out[0].backward(torch.ones(4))
comp_out = comp_mod(x1)
self.assertEqual(cnts.frame_count, 2)
comp_out[0].backward(torch.ones(4))
self.assertEqual(x0.grad, x1.grad)
def test_functools_arg_vary(self):
def pre_hook(grad, *, k):
return grad * k
hook = functools.partial(pre_hook, k=1)
@torch.compile(backend="eager", fullgraph=True)
def h(x):
y = x.mul(2)
y.register_hook(hook)
return y.mul(3)
with compiled_autograd.enable(torch.compile(backend="eager", fullgraph=True)):
x = torch.randn(2, requires_grad=True)
h(x).sum().backward()
orig_grad = x.grad
x.grad = None
hook = functools.partial(pre_hook, k=2)
h(x).sum().backward()
self.assertEqual(orig_grad * 2, x.grad)
def test_post_acc_grad_hook(self):
def hook(input_t):
input_t.mul_(input_t.grad)
input_t.grad.mul_(5)
def reg_and_mul(x, y):
x.register_post_accumulate_grad_hook(hook)
return x * y
cnts = None
def test_fn(fn):
fn(x, y)
b = torch.tensor([2.0, 2.0, 2.0], requires_grad=True)
x.backward(b)
if cnts:
self.assertEqual(cnts.frame_count, 1)
# These same exact assertions run on both eager and compiled
# X goes to x*2 becaue of mul_
self.assertEqual(x, torch.tensor([0.5, 0.5, 0.5]) * 2)
# This test proves grad aliasing works -
self.assertEqual(x.grad, b * 5)
# Eager values
x = torch.tensor([0.5, 0.5, 0.5], requires_grad=True)
y = torch.tensor([1.0, 2.0, 3.0], requires_grad=True)
test_fn(reg_and_mul)
# Compiled
for backend in ["eager", "aot_eager", "inductor"]:
for compiled_bwd in [False, True]:
torch._dynamo.reset()
x = torch.tensor([0.5, 0.5, 0.5], requires_grad=True)
y = torch.tensor([1.0, 2.0, 3.0], requires_grad=True)
cnts = torch._dynamo.testing.CompileCounterWithBackend(backend)
compiled_fn = torch._dynamo.optimize(cnts, nopython=True)(reg_and_mul)
compiled_bwd_ctx = (
compiled_autograd.enable(
torch.compile(backend=backend, fullgraph=True)
)
if compiled_bwd
else contextlib.nullcontext()
)
with compiled_bwd_ctx:
test_fn(compiled_fn)
if __name__ == "__main__":
from torch._dynamo.test_case import run_tests
run_tests()