[relanding again after fixing internal build]
Summary:
This might cause some new DDEs on call sites that do not use is_contiguous_or_false() or sym_is_contiguous()
but want to find those call sites to handle this properly by calling is_contiguous_or_false() and not is_contiguous() explitly when appropriate.
I had to fix one issue after removing the implicit size oblivious reasoning. here is context
we defined in this https://github.com/pytorch/pytorch/pull/157472 sym_is_contiguous to be the function computing contiguity for dynamic shapes in c++. It returns a symbolic expression that represents contiguity and guaranteed not to throw a DDE.
when people call is_contiguous we do sym_is_contiguous().guard_bool()
when people call is_contiguous_or_false we do sym_is_contiguous().guard_or_false()
one issue not handled well was this path
```
c10::SymBool TensorImpl::sym_is_contiguous_custom(
at::MemoryFormat memory_format) const {
if (C10_UNLIKELY(matches_python_custom(SizesStridesPolicy::CustomStrides))) {
return pyobj_slot_.load_pyobj_interpreter()->is_contiguous(
this, memory_format);
}
return sym_is_contiguous_default(memory_format);
}
```
namely if we call sym_is_contiguous_custom but we have matches_python_custom(SizesStridesPolicy::CustomStrides) return true , then we used to call is_contiguous(this, memory_format);
This used to go through the load_pyobj_interpreter and end up calling the python is_contiguous call which used implicit size oblivious reasoning.
once we removed that implicit size oblivious reasoning, the right thing we want is to call
return pyobj_slot_.load_pyobj_interpreter()->sym_is_contiguous(this, memory_format);
otherwise we would get DDE even if the caller is doing sym_is_contiguous.
so I had to define it for pyinterpreter, and then I had to override it for nested tensors.
Approved by: https://github.com/ezyang
Test Plan:
contbuild & OSS CI, see e444cd24d4
Rollback Plan:
Differential Revision: D80435179
Pull Request resolved: https://github.com/pytorch/pytorch/pull/160869
Approved by: https://github.com/ezyang
This might cause some new DDEs on call sites that do not use is_contiguous_or_false() or sym_is_contiguous()
but want to find those call sites to handle this properly by calling is_contiguous_or_false() and not is_contiguous() explitly when appropriate.
I had to fix one issue after removing the implicit size oblivious reasoning. here is context
we defined in this https://github.com/pytorch/pytorch/pull/157472 sym_is_contiguous to be the function computing contiguity for dynamic shapes in c++. It returns a symbolic expression that represents contiguity and guaranteed not to throw a DDE.
when people call is_contiguous we do sym_is_contiguous().guard_bool()
when people call is_contiguous_or_false we do sym_is_contiguous().guard_or_false()
one issue not handled well was this path
```
c10::SymBool TensorImpl::sym_is_contiguous_custom(
at::MemoryFormat memory_format) const {
if (C10_UNLIKELY(matches_python_custom(SizesStridesPolicy::CustomStrides))) {
return pyobj_slot_.load_pyobj_interpreter()->is_contiguous(
this, memory_format);
}
return sym_is_contiguous_default(memory_format);
}
```
namely if we call sym_is_contiguous_custom but we have matches_python_custom(SizesStridesPolicy::CustomStrides) return true , then we used to call is_contiguous(this, memory_format);
This used to go through the load_pyobj_interpreter and end up calling the python is_contiguous call which used implicit size oblivious reasoning.
once we removed that implicit size oblivious reasoning, the right thing we want is to call
return pyobj_slot_.load_pyobj_interpreter()->sym_is_contiguous(this, memory_format);
otherwise we would get DDE even if the caller is doing sym_is_contiguous.
so I had to define it for pyinterpreter, and then I had to override it for nested tensors.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/159197
Approved by: https://github.com/ezyang
Summary: We were getting DDE on reshape still!! i looked deeper and found an issue in _view_has_unbacked_input namely when input is [[,,]] it need to be normalized to [..]
Test Plan:
existing tests.
Rollback Plan:
Differential Revision: D79951119
Pull Request resolved: https://github.com/pytorch/pytorch/pull/160255
Approved by: https://github.com/bobrenjc93
Python dispatcher is not always enabled in fake tensors and have to be called explicitly.
While it should be, it requires some work to get all tests working.
I have been running in several issues where I add to add enable_python_dispatcher ex
XLA, Helom ..etc to avoid issues related to that for the view specifically i moved it to fake tensor impl.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/158406
Approved by: https://github.com/bobrenjc93
When select has data dependent input, we cant tell if the actual index shall be index+size or index.
to avoid throwing dde, we allocate a new unbacked symbol to represent the storage offset of the
output view and we compute its value dynamically at runtime when inductor is lowered.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/157605
Approved by: https://github.com/ColinPeppler
When select has data dependent input, we cant tell if the actual index shall be index+size or index.
to avoid throwing dde, we allocate a new unbacked symbol to represent the storage offset of the
output view and we compute its value dynamically at runtime when inductor is lowered.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/157605
Approved by: https://github.com/ColinPeppler
Handles GC for non-strict draft export; GPU memory usage shouldn't be much more than eager mode + input tensors now.
While trying to do draft export CPU offloading, I found out GC is feasible, because in non-strict, there's 2 places holding references to a `.real_tensor` attribute:
1) the FakeTensors in fake tensor prop, but these are held by the actual variables in the model's forward call, and so the real tensor gets gc-ed along with the fake one when the variable goes out of scope.
2) A clone of the fake tensor in 1) stored in `proxy.node.meta["val"]`, which was added in https://github.com/pytorch/pytorch/pull/150948. But we didn't actually need to store them on intermediate values; the placeholders are enough for retracing/lowering.
Avoiding storing the intermediate values in 2), the values in 1) should be naturally GC-ed, and the real-tensor memory usage for non-strict should be pretty similar to eager computation?
Strict still OOMs; dynamo still holds these in variable tracking, and not sure how to GC those.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/154630
Approved by: https://github.com/angelayi, https://github.com/yushangdi
## What
- use `definitely_contiguous_for_memory_format` instead of `is_contiguous` when the non-contiguous case is fine if we encounter a DDE.
- use ref's contiguous over Aten's contiguous because Aten's version will DDE and stop tracing. ref's version will use `definitely_contiguous_for_memory_format` and clone if there's a DDE.
## Example DDEs
- Fixed with `definitely_contiguous_for_memory_format` in `fast_binary_impl`
```
torch._dynamo.exc.UserError: Could not guard on data-dependent expression Eq((u0//387), 0) (unhinted: Eq((u0//387), 0)). (Size-like symbols: u0)
Caused by: layer_norm = self.layer_norm(linear) # caffe2/test/export/test_export.py:4566 in forward (_subclasses/fake_impls.py:1022 in fast_binary_impl)
```
- Fixed with `refs.contiguous` instead of calling aten's contiguous (that'd require a bigger re-write in Aten)
```
File "c10/core/TensorImpl.h", line 825, in torch::autograd::THPVariable_contiguous(_object*, _object*, _object*)
File "c10/core/SymbolicShapeMeta.h", line 87, in c10::TensorImpl::is_contiguous_default(c10::MemoryFormat) const
File "c10/core/SymbolicShapeMeta.cpp", line 250, in c10::SymbolicShapeMeta::init_is_contiguous() const
torch.fx.experimental.symbolic_shapes.GuardOnDataDependentSymNode: Could not guard on data-dependent expression Eq(128*((u0//387)), 0) (unhinted: Eq(128*((u0//387)), 0)). (Size-like symbols: u0)
Caused by: (_refs/__init__.py:3302 in native_layer_norm)
```
- Fixed with `definitely_contiguous_for_memory_format` in ref's contiguous
```
torch.fx.experimental.symbolic_shapes.GuardOnDataDependentSymNode: Could not guard on data-dependent expression 387*((u0//387)) < 2 (unhinted: 387*((u0//387)) < 2). (Size-like symbols: u0)
Caused by: (_prims_common/__init__.py:279 in is_contiguous)
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/155260
Approved by: https://github.com/laithsakka
ghstack dependencies: #155499
Handles GC for non-strict draft export; GPU memory usage shouldn't be much more than eager mode + input tensors now.
While trying to do draft export CPU offloading, I found out GC is feasible, because in non-strict, there's 2 places holding references to a `.real_tensor` attribute:
1) the FakeTensors in fake tensor prop, but these are held by the actual variables in the model's forward call, and so the real tensor gets gc-ed along with the fake one when the variable goes out of scope.
2) A clone of the fake tensor in 1) stored in `proxy.node.meta["val"]`, which was added in https://github.com/pytorch/pytorch/pull/150948. But we didn't actually need to store them on intermediate values; the placeholders are enough for retracing/lowering.
Avoiding storing the intermediate values in 2), the values in 1) should be naturally GC-ed, and the real-tensor memory usage for non-strict should be pretty similar to eager computation?
Strict still OOMs; dynamo still holds these in variable tracking, and not sure how to GC those.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/154630
Approved by: https://github.com/angelayi, https://github.com/yushangdi
Summary: We need real_tensor on the FakeTensor in node.meta["val"] in order to aot_compile the draft exported programs. Otherwise, we cannot propagate real tensors even when fake_mode.propagate_real_tensors = True.
This also fixes real tensor propagation in `run_decomposition()`.
Test Plan:
```
buck2 run @mode/dev-nosan caffe2/test:test_export -- -r test_dedup_data_dependent_failure
```
Differential Revision: D72732714
Pull Request resolved: https://github.com/pytorch/pytorch/pull/150948
Approved by: https://github.com/angelayi
Summary:
When we divide a FakeTensor by an integer using the fast op implementation, the type promotion should be `ELEMENTWISE_TYPE_PROMOTION_KIND.INT_TO_FLOAT` so we get a float when dividing an int FakeTensor by an integer.
```
FAST = get_fast_op_impls()
fast_div = FAST[torch.ops.aten.div.Tensor]
fast_div(fake_tensor, some_int)
```
Test Plan:
```
python test/test_fake_tensor.py -k test_fast_div
```
Differential Revision: D72667430
Pull Request resolved: https://github.com/pytorch/pytorch/pull/150874
Approved by: https://github.com/angelayi
