functional compiled autograd (pytorch#144707)

This PR squashes together the following commits:

pytorch#144115
pytorch#143417
pytorch#143405
pytorch#143387
pytorch#143304
pytorch#143296

This is a refactor of compiled autograd to use "functional autograd". The end goal is that it gets compiled autograd's initial capture to stop specializing on Tensor metadata, therefore allowing compiled autograd to better handle Tensor subclasses.

For more information, please read the commit messages for each PR.

Pull Request resolved: pytorch#144707
Approved by: https://github.com/bdhirsh, https://github.com/xmfan, https://github.com/jansel

aten/src/ATen/TensorGeometry.h

@@ -37,6 +37,16 @@ struct TORCH_API TensorGeometry {
         has_symbolic_sizes_strides_(
             t.unsafeGetTensorImpl()->has_symbolic_sizes_strides()) {}
 
+  explicit TensorGeometry(
+      std::vector<at::SymInt> sizes,
+      std::vector<at::SymInt> strides,
+      at::SymInt storage_offset)
+      : sizes_(std::move(sizes)),
+        strides_(std::move(strides)),
+        storage_offset_(std::move(storage_offset)) {
+    recompute();
+  }
+
   // true if the tensor is contiguous
   bool is_contiguous() const;
 

build_variables.bzl

@@ -138,6 +138,7 @@ core_trainer_sources = [
     "torch/csrc/autograd/variable.cpp",
     "torch/csrc/autograd/utils/warnings.cpp",
     "torch/csrc/autograd/jit_decomp_interface.cpp",
+    "torch/csrc/dynamo/compiled_autograd.cpp",
     "torch/csrc/jit/frontend/name_mangler.cpp",
     "torch/csrc/jit/ir/type_hashing.cpp",
     "torch/csrc/jit/serialization/pickler.cpp",

test/dynamo/test_backward_higher_order_ops.py

@@ -121,23 +121,30 @@ def fn(x, y):
                 out.backward(grad_out)
             actual = normalize_gm(graph.print_readable(False))
             self.assertEqual(x.grad, grad_out * grad_out)
-            self.assertExpectedInline(
-                actual,
-                """\
+            if backend in ["aot_eager", "inductor"]:
+                self.assertExpectedInline(
+                    actual,
+                    """\
 class GraphModule(torch.nn.Module):
     def forward(self, L_inputs_ : list):
         l_inputs_ = L_inputs_
 
-        getitem: "f32[s0]" = l_inputs_[0];  l_inputs_ = None
+        getitem: "f32[2]" = l_inputs_[0];  l_inputs_ = None
 
-        new_grad: "f32[s0]" = torch.clone(getitem)
+        validate_outputs = torch__dynamo_compiled_autograd_ops_validate_outputs([getitem], [((None, None, device(type='cpu'), 6, 0, None), [2], False)]);  getitem = None
+        getitem_3: "f32[2]" = validate_outputs[0];  validate_outputs = None
 
-        result: "f32[s0]" = getitem * getitem;  getitem = None
+        call_aot_bwd_prologue = torch__dynamo_compiled_autograd_call_aot_bwd_prologue((), [], getitem_3);  getitem_3 = None
+        getitem_5: "f32[2]" = call_aot_bwd_prologue[0];  call_aot_bwd_prologue = None
 
-        new_grad_1: "f32[s0]" = torch.clone(result);  result = None
+        new_grad: "f32[2]" = torch.clone(getitem_5)
+
+        result: "f32[2]" = getitem_5 * getitem_5;  getitem_5 = None
+
+        new_grad_1: "f32[2]" = torch.clone(result);  result = None
         return (new_grad, new_grad_1)
 """,
-            )
+                )
 
             graph = None
 
@@ -162,7 +169,7 @@ def inner_compiler(gm_, example_inputs_):
                 gm, backend=inner_compiler, fullgraph=True, dynamic=True
             )
 
-        for backend in ["eager", "aot_eager", "inductor"]:
+        for backend in ["inductor"]:
             torch._dynamo.reset()
             x = torch.tensor([0.5, 0.5], requires_grad=True)
             y = torch.tensor([0.5, 0.5], requires_grad=True)
@@ -187,26 +194,33 @@ def fn(x, y):
             actual = normalize_gm(graph.print_readable(False))
             self.assertEqual(obj.counter, 1)
             self.assertEqual(x.grad, grad_out + grad_out)
-            self.assertExpectedInline(
-                actual,
-                """\
+            if backend in ["aot_eager", "inductor"]:
+                self.assertExpectedInline(
+                    actual,
+                    """\
 class GraphModule(torch.nn.Module):
-    def forward(self, L_inputs_ : list, L_hooks_0_keywords_fn_keywords_obj_counter: "Sym(s1)"):
+    def forward(self, L_inputs_ : list, L_hooks_1_keywords_fn_keywords_obj_counter: "Sym(s1)"):
         l_inputs_ = L_inputs_
-        l_hooks_0_keywords_fn_keywords_obj_counter = L_hooks_0_keywords_fn_keywords_obj_counter
+        l_hooks_1_keywords_fn_keywords_obj_counter = L_hooks_1_keywords_fn_keywords_obj_counter
 
-        getitem: "f32[s0]" = l_inputs_[0];  l_inputs_ = None
+        getitem: "f32[2]" = l_inputs_[0];  l_inputs_ = None
 
-        new_grad: "f32[s0]" = torch.clone(getitem)
+        validate_outputs = torch__dynamo_compiled_autograd_ops_validate_outputs([getitem], [((None, None, device(type='cpu'), 6, 0, None), [2], False)]);  getitem = None
+        getitem_3: "f32[2]" = validate_outputs[0];  validate_outputs = None
 
-        add: "Sym(s1 + 1)" = l_hooks_0_keywords_fn_keywords_obj_counter + 1;  l_hooks_0_keywords_fn_keywords_obj_counter = None
+        call_aot_bwd_prologue = torch__dynamo_compiled_autograd_call_aot_bwd_prologue((), [], getitem_3);  getitem_3 = None
+        getitem_5: "f32[2]" = call_aot_bwd_prologue[0];  call_aot_bwd_prologue = None
 
-        result: "f32[s0]" = getitem * getitem;  getitem = None
+        new_grad: "f32[2]" = torch.clone(getitem_5)
 
-        new_grad_1: "f32[s0]" = torch.clone(result);  result = None
+        add: "Sym(s1 + 1)" = l_hooks_1_keywords_fn_keywords_obj_counter + 1;  l_hooks_1_keywords_fn_keywords_obj_counter = None
+
+        result: "f32[2]" = getitem_5 * getitem_5;  getitem_5 = None
+
+        new_grad_1: "f32[2]" = torch.clone(result);  result = None
         return (new_grad, new_grad_1, add)
 """,
-            )
+                )
 
             out = fn(x, y)
             out.backward(grad_out)

test/inductor/test_compiled_autograd.py

@@ -22,6 +22,7 @@
 from torch._dynamo import compiled_autograd, config
 from torch._dynamo.backends.debugging import aot_eager
 from torch._dynamo.device_interface import get_interface_for_device
+from torch._dynamo.testing import normalize_gm
 from torch._dynamo.utils import counters
 from torch._inductor import config as inductor_config
 from torch._inductor.test_case import run_tests, TestCase
@@ -2821,8 +2822,11 @@ def test_cudagraphs_cpu_scalar_used_in_cpp_custom_op(self, load_inline):
             opt_bwd()
 
         self.assertEqual(counters["compiled_autograd"]["captures"], 1)
-        # always safe to move, since we trace into the autograd::function bwd and can see if it's only used by aten ops
-        self.assertEqual(counters["inductor"]["cudagraph_skips"], 0)
+        # Compiled autograd's initial capture lifts custom C++ autograd::Function bwd instead of tracing
+        # into it. We must skip since we do not know if the cpu scalar will be used only in ATen/prim ops.
+        # In the future, we can consider having a cpu scalar movement pass sometime after we trace
+        # into the custom C++ autograd::Function (like in AOTDispatcher)
+        self.assertEqual(counters["inductor"]["cudagraph_skips"], 1)
 
     def test_logs(self):
         logs, ctx = logs_to_string(
@@ -2941,12 +2945,11 @@ def forward(model, x):
 
         expected_logs = [
             "code: CompiledFunctionBackward (NodeCall 2)",
+            "code: CompiledFunctionBackward0 (NodeCall 2)",
             "aot0_primals_3",
             "aot0_relu",
             "aot0_le",
             "aot0_permute_2",
-            "code: CompiledFunctionBackward0 (NodeCall 2)",
-            "aot0_tangents_1",
             "aot0_full_default",
             "aot0_where",
             "aot0_mm",
@@ -2996,20 +2999,17 @@ def f(x):
 
         expected_logs = [
             "CompiledFunctionBackward1",
-            "aot1_tangents_1",
             "aot1_sin_1",
-            "aot1_primals_2",
             "aot1_neg",
             "aot0_tangents_2",
             "aot1_cos_1",
-            "aot1_primals_1",
             "aot0_tangents_1",
             "CompiledFunctionBackward0",
+            "aot0_sin_1",
             "aot0_neg",
-            "aot0_sin",
             "aot0_mul",
+            "aot0_cos_1",
             "aot0_mul_1",
-            "aot0_cos",
             "aot0_add",
         ]
 
@@ -3154,6 +3154,120 @@ def fn():
 
         self.assertEqual(sum(1 for e in unexpected_logs if e in logs.getvalue()), 0)
 
+    def test_tensor_subclass_basic(self):
+        from torch.testing._internal.two_tensor import TwoTensor, TwoTensorMode
+
+        with torch.library._scoped_library("mylib", "FRAGMENT") as lib:
+            lib.define("to_twotensor(Tensor a, Tensor b) -> Tensor")
+            lib.define("from_twotensor(Tensor c) -> (Tensor, Tensor)")
+
+            def to_twotensor_backward(ctx, grad):
+                return torch.ops.mylib.from_twotensor(grad)
+
+            def from_twotensor_backward(ctx, grad_a, grad_b):
+                raise AssertionError("shouldn't get hit")
+
+            torch.library.register_autograd(
+                "mylib::to_twotensor", to_twotensor_backward, lib=lib
+            )
+            torch.library.register_autograd(
+                "mylib::from_twotensor", from_twotensor_backward, lib=lib
+            )
+
+            @torch.library.register_torch_dispatch(
+                "mylib::to_twotensor", TwoTensorMode, lib=lib
+            )
+            def _(_0, _1, _2, args, kwargs):
+                assert not kwargs
+                a, b = args
+                return TwoTensor(a.clone(), b.clone())
+
+            @torch.library.register_torch_dispatch(
+                "mylib::from_twotensor", TwoTensor, lib=lib
+            )
+            def _(_0, _1, _2, args, kwargs):
+                assert not kwargs
+                (c,) = args
+                return c.a.clone(), c.b.clone()
+
+            @torch.compile(backend="aot_eager", fullgraph=True)
+            def fn(x):
+                return x * x + 2
+
+            param1 = torch.randn(4, 4, requires_grad=True)
+            param2 = torch.randn(4, 4, requires_grad=True)
+            with TwoTensorMode():
+                x = torch.ops.mylib.to_twotensor(param1, param2)
+
+            inner_compiler_fn = make_compiler_fn(fullgraph=True, backend="aot_eager")
+            graphs = []
+
+            def compiler_fn(gm):
+                graphs.append(gm)
+                return inner_compiler_fn(gm)
+
+            with compiled_autograd._enable(compiler_fn):
+                res = fn(x)
+                res.sum().backward()
+
+            self.assertEqual(param1.grad, 2 * param1)
+            self.assertEqual(param2.grad, 2 * param2)
+            self.assertEqual(len(graphs), 1)
+
+            graph_code = normalize_gm(graphs[0].print_readable(print_output=False))
+            # The graph should have make_subclass calls in it.
+            self.assertExpectedInline(
+                graph_code,
+                """\
+class CompiledAutograd0(torch.nn.Module):
+    def forward(self, inputs, sizes, scalars, hooks):
+        getitem = inputs[0]
+        getitem_1 = inputs[1]
+        getitem_2 = inputs[2]
+        getitem_3 = inputs[3]
+        getitem_4 = inputs[4];  inputs = None
+
+        validate_outputs = torch__dynamo_compiled_autograd_ops_validate_outputs([getitem], [((None, None, device(type='cpu'), 6, 0, None), [], True)]);  getitem = None
+        getitem_5 = validate_outputs[0];  validate_outputs = None
+
+        sum_backward0 = torch__dynamo_compiled_autograd_ops_SumBackward0([getitem_5], [True], [4, 4]);  getitem_5 = None
+        getitem_6 = sum_backward0[0];  sum_backward0 = None
+        validate_outputs_1 = torch__dynamo_compiled_autograd_ops_validate_outputs([getitem_6], [((None, None, device(type='cpu'), 6, 0, None), [4, 4], True)]);  getitem_6 = None
+        getitem_7 = validate_outputs_1[0];  validate_outputs_1 = None
+
+        getitem_8 = hooks[0];  getitem_8 = None
+        call_aot_bwd_prologue = torch__dynamo_compiled_autograd_call_aot_bwd_prologue((getitem_1, getitem_2), [], getitem_7);  getitem_1 = getitem_2 = getitem_7 = None
+        aot0_primals_1 = call_aot_bwd_prologue[0]
+        aot0_primals_2 = call_aot_bwd_prologue[1]
+        aot0_tangents_1 = call_aot_bwd_prologue[2]
+        aot0_tangents_2 = call_aot_bwd_prologue[3];  call_aot_bwd_prologue = None
+
+        aot0_mul_2 = torch.ops.aten.mul.Tensor(aot0_tangents_1, aot0_primals_1);  aot0_tangents_1 = aot0_primals_1 = None
+        aot0_mul_3 = torch.ops.aten.mul.Tensor(aot0_tangents_2, aot0_primals_2);  aot0_tangents_2 = aot0_primals_2 = None
+
+        aot0_add_2 = torch.ops.aten.add.Tensor(aot0_mul_2, aot0_mul_2);  aot0_mul_2 = None
+        aot0_add_3 = torch.ops.aten.add.Tensor(aot0_mul_3, aot0_mul_3);  aot0_mul_3 = None
+
+        make_subclass = torch__dynamo_compiled_autograd_make_subclass(aot0_add_2, aot0_add_3);  aot0_add_2 = aot0_add_3 = None
+
+        getitem_13 = hooks[1];  hooks = None
+        call_backward = torch__dynamo_external_utils_call_backward(getitem_13, (), make_subclass);  getitem_13 = make_subclass = None
+        getitem_16 = call_backward[0]
+        getitem_17 = call_backward[1];  call_backward = None
+        validate_outputs_2 = torch__dynamo_compiled_autograd_ops_validate_outputs([getitem_16, getitem_17], [((None, None, device(type='cpu'), 6, 0, None), [4, 4], False), ((None, None, device(type='cpu'), 6, 0, None), [4, 4], False)]);  getitem_16 = getitem_17 = None
+        getitem_19 = validate_outputs_2[0]
+
+        accumulate_grad__1 = torch.ops.inductor.accumulate_grad_.default(getitem_4, getitem_19);  getitem_4 = getitem_19 = accumulate_grad__1 = None
+
+        getitem_20 = validate_outputs_2[1];  validate_outputs_2 = None
+
+        accumulate_grad_ = torch.ops.inductor.accumulate_grad_.default(getitem_3, getitem_20);  getitem_3 = getitem_20 = accumulate_grad_ = None
+
+        _exec_final_callbacks_stub = torch__dynamo_external_utils__exec_final_callbacks_stub();  _exec_final_callbacks_stub = None
+        return []
+""",  # noqa: B950
+            )
+
     # https://github.com/pytorch/pytorch/issues/138920
     def test_compiled_autograd_does_not_specialize_on_bw_symints(self):
         class Mod(torch.nn.Module):
@@ -3247,7 +3361,7 @@ def inner_compiler(gm_, example_inputs_):
         # because we ignore all of these guards anyway in CA.
         # Once we stop using make_fx in CA, we won't have to worry about this specialization.
         view_nodes = graphs[1].graph.find_nodes(
-            op="call_function", target=torch.ops.aten.view.default
+            op="call_function", target=torch.ops.aten.reshape.default
         )
         # First 2 view nodes have a first argument that is a SymInt, not an int burned into the graph
         self.assertTrue(isinstance(view_nodes[0].args[1][0], torch.fx.Node))
@@ -3640,6 +3754,7 @@ def wrap_test_class(orig_cls):
     "test_tp_compile_comm_reordering",
     "test_unwrap_async_collective_tensor_tangent",
     # Uncategorized
+    "test_not_implemented_grad",  # Dynamo changes the types of exceptions
 }
 
 if not HAS_CUDA:

test/inductor/test_distributed_patterns.py

@@ -337,7 +337,9 @@ def test_module_backward_hooks_eager(self):
         self.assertEqual(fw_cnt.frame_count, 1)
         self.assertEqual(fw_cnt.op_count, 5)
         self.assertEqual(bw_cnt.frame_count, 2)  # grad=None and grad!=None
-        self.assertEqual(bw_cnt.op_count, 48)
+        self.assertEqual(
+            bw_cnt.op_count, 72
+        )  # Number of ops in the Dynamo-produced graphs
 
     def test_module_backward_hooks_aot(self):
         m1, inp1 = init_module_bw_hooks(True)