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This PR adds support for `enable_grad`/`no_grad`/`autocast` context managers getting properly traced in `pre_dispatch` tracing. The stuff in this PR includes: - I added a torch function mode that runs during make_fx pre_dispatch tracing, `ProxyTorchFunctionMode`. It directly intercepts the torch ops that run during the above context managers, and adds them to the current graph instead of executing them - `enable_grad` and `no_grad` currently desugar into `torch._C.set_grad_enabled(bool)`, but this API isn't currently overrideable by torch function so I added the ability to interpose there - the `torch.amp` context managers don't currently have a nice equivalent, like `set_autocast_enabled(state)`, so I ended up adding two new API's: `torch.amp._set_autocast_enabled` and `torch.amp._set_autocast_disabled`. If you look at how the context manager is implemented, it ends up calling several different state-changing functions, some of which depend on the backend - so I figured that it would be cleaner just to add a new API (that should probably only be used by tracing) - but open to feedback - I added a new dynamo backend, `compile(backend="pre_dispatch_eager")`. When pre_dispatch tracing becomes always-on in inductor, it will be another potential surface for bugs. I also added a test file for it (`test/dynamo/test_pre_dispatch.py`). Pull Request resolved: https://github.com/pytorch/pytorch/pull/103024 Approved by: https://github.com/ezyang
77 lines
2.1 KiB
Python
77 lines
2.1 KiB
Python
# Owner(s): ["module: dynamo"]
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import torch
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import torch._dynamo
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import torch._dynamo.test_case
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class PreDispatchTests(torch._dynamo.test_case.TestCase):
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def test_no_grad_simple(self):
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def f(a):
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b = a.sin()
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with torch.no_grad():
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c = b.cos()
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return b * c.sin()
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f_compiled = torch.compile(f, backend="pre_dispatch_eager")
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a_ref = torch.randn(4, requires_grad=True)
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a_test = a_ref.clone().detach().requires_grad_(True)
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out_ref = f(a_ref)
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out_test = f_compiled(a_test)
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self.assertEqual(out_ref, out_test)
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out_ref.sum().backward()
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out_test.sum().backward()
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self.assertEqual(a_ref.grad, a_test.grad)
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def test_enable_grad_and_no_grad(self):
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def f(a):
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b = a * 2
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with torch.no_grad():
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c = b * 3
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with torch.enable_grad():
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d = c * 4
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e = d * 5
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return b + c + d + e
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f_compiled = torch.compile(f, backend="pre_dispatch_eager")
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a_ref = torch.randn(4, requires_grad=True)
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a_test = a_ref.clone().detach().requires_grad_(True)
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out_ref = f(a_ref)
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out_test = f_compiled(a_test)
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self.assertEqual(out_ref, out_test)
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out_ref.sum().backward()
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out_test.sum().backward()
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self.assertEqual(a_ref.grad, a_test.grad)
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def test_autocast_simple(self):
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def f(a):
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b = a * 2
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with torch.amp.autocast(device_type="cpu"):
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c = torch.matmul(b, b)
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return b + c
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f_compiled = torch.compile(f, backend="pre_dispatch_eager")
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a_ref = torch.randn(4, device="cpu", requires_grad=True)
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a_test = a_ref.clone().detach().requires_grad_(True)
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out_ref = f(a_ref)
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out_test = f_compiled(a_test)
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self.assertEqual(out_ref, out_test)
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out_ref.sum().backward()
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out_test.sum().backward()
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self.assertEqual(a_ref.grad, a_test.grad)
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if __name__ == "__main__":
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from torch._dynamo.test_case import run_tests
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run_tests()
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