`grad_dtype` is a new attribute on Tensor to control gradient dtype:
- Access/setting is leaf-only.
- grad_dtype is respected when (1) when assigning to .grad, and (2) in the engine after the previous node produces incoming gradients for AccumulateGrad. (See table below for details)
- Not setting grad_dtype preserves the current behavior. Accessing it returns `t.dtype`
- `grad_dtype` cannot be set when there is already a `.grad` present and the dtypes conflict.
| `grad_dtype` setting | Setting `.grad` manually | Incoming gradient from autograd engine |
|-----------------------|--------------------------|-----------------------------------------|
| **Default (tensor’s dtype)** | `.grad` must match tensor’s dtype | Engine casts incoming grad to tensor’s dtype |
| **Set to specific dtype** | `.grad` must match that dtype | Engine casts incoming grad to the specified dtype |
| **Set to `None`** | `.grad` may be any dtype | Engine does not cast; accepts incoming grad dtype as-is |
Pull Request resolved: https://github.com/pytorch/pytorch/pull/162815
Approved by: https://github.com/albanD
This PR is a bit more involved but effectively works to drastically simplify PyObjectSlot and PyInterpreter.
1) For PyObjectSlot we now use a global pyinterpreter since there only is one. From here we change all of the call sites to rely on this assumption.
2) We also remove the "tags" of the PyInterpreter by deprecating `PyInterpreterStatus`.
For the reviewer, sadly it seems like `functorch/csrc/dim/dim.cpp` needed to get linted, so there is an unreadable amount of changes there. Fortunately, the only actual change in the file is as follows which just removes `getPyInterpreter()` from the `check_pyobj` call.
```
mpy::handle handle_from_tensor(Arena& A, TensorRef t) {
- // fast case: tensor is live in python
- std::optional<PyObject*> mb_obj =
- t->unsafeGetTensorImpl()->pyobj_slot()->check_pyobj(getPyInterpreter(), /*ignore_hermetic_tls=*/false);
- if (mb_obj.has_value() && !t->unsafeGetTensorImpl()->pyobj_slot()->owns_pyobj()) {
- return *mb_obj;
- }
- return A.autorelease(mpy::object::checked_steal(THPVariable_Wrap(*t)));
-}
-}
+ // fast case: tensor is live in python
+ std::optional<PyObject*> mb_obj =
+ t->unsafeGetTensorImpl()->pyobj_slot()->check_pyobj(
+ /*ignore_hermetic_tls=*/false);
+ if (mb_obj.has_value() &&
+ !t->unsafeGetTensorImpl()->pyobj_slot()->owns_pyobj()) {
+ return *mb_obj;
+ }
+ return A.autorelease(mpy::object::checked_steal(THPVariable_Wrap(*t)));
+}
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/158427
Approved by: https://github.com/albanD
This PR is a bit more involved but effectively works to drastically simplify PyObjectSlot and PyInterpreter.
1) For PyObjectSlot we now use a global pyinterpreter since there only is one. From here we change all of the call sites to rely on this assumption.
2) We also remove the "tags" of the PyInterpreter by deprecating `PyInterpreterStatus`.
For the reviewer, sadly it seems like `functorch/csrc/dim/dim.cpp` needed to get linted, so there is an unreadable amount of changes there. Fortunately, the only actual change in the file is as follows which just removes `getPyInterpreter()` from the `check_pyobj` call.
```
mpy::handle handle_from_tensor(Arena& A, TensorRef t) {
- // fast case: tensor is live in python
- std::optional<PyObject*> mb_obj =
- t->unsafeGetTensorImpl()->pyobj_slot()->check_pyobj(getPyInterpreter(), /*ignore_hermetic_tls=*/false);
- if (mb_obj.has_value() && !t->unsafeGetTensorImpl()->pyobj_slot()->owns_pyobj()) {
- return *mb_obj;
- }
- return A.autorelease(mpy::object::checked_steal(THPVariable_Wrap(*t)));
-}
-}
+ // fast case: tensor is live in python
+ std::optional<PyObject*> mb_obj =
+ t->unsafeGetTensorImpl()->pyobj_slot()->check_pyobj(
+ /*ignore_hermetic_tls=*/false);
+ if (mb_obj.has_value() &&
+ !t->unsafeGetTensorImpl()->pyobj_slot()->owns_pyobj()) {
+ return *mb_obj;
+ }
+ return A.autorelease(mpy::object::checked_steal(THPVariable_Wrap(*t)));
+}
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/158427
Approved by: https://github.com/albanD
This word appears often in class descriptions and is not consistently spelled. Update comments and some function names to use the correct spelling consistently. Facilitates searching the codebase.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/155944
Approved by: https://github.com/Skylion007
Enables clang-tidy rule [`misc-use-internal-linkage`](https://clang.llvm.org/extra/clang-tidy/checks/misc/use-internal-linkage.html). This new check was introduced in Clang-Tidy 18 and is available due to recent update of Clang-Tidy 19.
The check marks functions and variables used only in the translation unit as static. Therefore undesired symbols are not leaked into other units, more link time optimisations are possible and the resulting binaries may be smaller.
The detected violations were mostly fixed by using static. In other cases, the symbols were indeed consumed by others files, then their declaring headers were included. Still some declarations were wrong and have been fixed.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/148948
Approved by: https://github.com/Skylion007
Fixes a bug introduced in https://github.com/pytorch/pytorch/pull/137267
While the test ensures the finalizer did run to make sure things are cleared, the objects are not properly collected by the gc due to the faulty tp_clear implementation. So, while the finalizer did run, the object was still alive.
Fixing this by giving tp_clear the same treatment as tp_traverse and tp_dealloc on Tensor: make it a unique function that handles the full subclass hierarchy in one place.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/143203
Approved by: https://github.com/ezyang, https://github.com/colesbury
ghstack dependencies: #143202
This fixes 4 main issues:
- The way the cuda sanitizer handle it's state is weird. In particular, because the lifetime of the Mode is linked to the submodule, then this might outlive the python runtime and other modules loaded. On my current version, this even outlives the "sys" module. Given that I'm not sure the impact of changing this lifetime handling, I'm making the exit handler a no-op when python is already dying and thus no point cleaning up.
- Adds a "disable" method to be able to test after the mode is enabled.
- Fix `Tensor.as_sublass()` to properly disable modes when creating the new Tensor object just like we already do in `make_subclass` and `make_wrapper_subclass`. The change here is just to apply the exact same treatment to it.
- ~Fix `Tensor.as_subclass()` not to propagate autograd as there is no valid backward associated here.~ We have test that check that this behavior happen so I guess this is not an obvious bugfix and expected behavior. Reverted that change.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/138218
Approved by: https://github.com/ngimel
Fixes https://github.com/pytorch/pytorch/issues/136358
The bug here is that the Tensor object is actually 2 classes: `Tensor` from `_tensor.py` and `TensorBase` from c++.
Before this PR, they have the following gc methods:
Tensor:
- tp_clear subtype_clear
- tp_traverse THPVariable_subclass_traverse
- tp_dealloc THPVariable_subclass_dealloc
TensorBase:
- tp_clear THPVariable_clear
- tp_traverse THPFunction_traverse (fake function that is just an error)
- tp_dealloc object_dealloc
The problem is that when clear is called on the Tensor, subtype_clear is going to clear the things owned by the "Tensor" type, in particular, its `__dict__` attribute, before delegating to the TensorBase clear where we detect that resurrection needs to happen and skip it.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/137267
Approved by: https://github.com/ezyang, https://github.com/kshitij12345
### Before this PR:
`torch.utils.swap_tensors(a, b)` required the `use_count` of `a` and `b` to be 1
```python
a = torch.randn(2, 3, requires_grad=True)
b = torch.randn(2, 4)
out = a * 2
out.sum().backward()
# Calling swap_tensors here would fail due to the reference held by AccumulateGrad node, which is not cleaned up after backward
# torch.utils.swap_tensors(a, b)
del out
# Calling swap_tensors here would pass
torch.utils.swap_tensors(a, b)
```
### After this PR:
`torch.utils.swap_tensors(a, b)` requires the `use_count` of `a` and `b` to be 1 or 2 IF the second reference is held by `AccumulateGrad`
A pre-hook will be registered on the `AccumulateGrad` node so that it will fail if it is called (i.e. if user attempts to backward through the graph).
```python
a = torch.randn(2, 3, requires_grad=True)
b = torch.randn(2, 4)
out = a * 2
out.sum().backward()
# Calling swap_tensors here is ok
torch.utils.swap_tensors(a, b)
# If we ever backward to the AccumulateGrad node it will error that it was poisoned by swap_tensors
```
### Application to `nn.Module`
This issue is especially pertinent in context of `nn.Module` where parameters will have `AccumulateGrad` nodes initialized after forward. Specifically, this is intended to address https://github.com/pytorch/pytorch/pull/126814#issuecomment-2127777866. Previously, this would fail at the `m.cpu()` but we want users to be able to do something like the following, and instead raise an error if the user ever attempts to backward through the poisoned `AccumulateGrad` node
```python
import torch
import torch.nn as nn
m = nn.Linear(3, 5)
inp = torch.randn(2, 3)
out = m(inp)
out.sum().backward()
m.cpu()
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/127313
Approved by: https://github.com/soulitzer
This is mainly:
- Fix refcount access macro
- Hide all the Dynamo code that needs update as usual
- Add _PyWeakref_ClearRef as an extern provided by CPython. Including the pycore header that defines it would require raw c include shenanigans that I don't think are worth it.
This allows to build both with regular and nogil version of cpython. Both
Note that this requires the 3.13 branch at least past [d3094744d40de2deefbda9b1996d5029c9ebf0b0](d3094744d4) which we need for mimalloc include and weakref function being exposed.
debug-only issues in pybind11 with PyMem_MALLOC vs PyObject_MALLOC being should be synced either by updating pybind or cpython. @colesbury I can send a PR to ifdef the proper use in pybind if you think that this is the best solution here?
Pull Request resolved: https://github.com/pytorch/pytorch/pull/126033
Approved by: https://github.com/colesbury
