When fakifying a grad tracking tensor, if the level is -2 (sentinel
value) we can just unwrap the grad tensor and return a fake version of
it. In this PR, we update the `assert_metadata_eq` to not compare if
the grad tensor and the unwrapped ones are leafs or not, as this may
not be always true.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/122728
Approved by: https://github.com/zou3519
At a high level, the goal of this refactor was to make it so that `MetaConverter.__call__` has a straightforward code structure in three steps: (1) check if we support doing meta conversion, (2) describe the tensor into MetaTensorDesc, (3) call `meta_tensor` on MetaTensorDesc. However, this is not so easy to do, because there is a big pile of special cases for functional tensor inside `__call__`.
The primarily complication is handling the ambient functionalization state: specifically, the functorch dynamic layer stack and the Python functionalization dispatch. The old code demands that meta tensor conversion happen with this state disabled. But I discovered that when I reconstruct functorch tensors it demands that the functorch layers be active; in fact a batch tensor will have a pointer to the internal functorch layer.
I had some discussion with Richard Zou about what code structure here makes sense. In particular, one of the goals of the refactor here is that I can inflate MetaTensorDesc from an entirely different process, which may not have all of the functorch layers activated at the time we do reconstruction. So it seems to me that we should make it explicit in MetaTensorDesc that there was some functorch layer active at the time the functorch tensor was serialized, so that we could potentially know we need to reconstruct these layers on the other side. This is NOT implemented yet, but there's some notes about how potentially it could proceed. But the important thing here is we SHOULD disable everything when we run `meta_tensor`, and internally be responsible for restoring the stack. Actually, the necessary infra bits in functorch don't exist to do this, so I added some simple implementations in pyfunctorch.py.
The rest is splitting up the manipulations on tensor (we do things like sync the real tensor before describing it; Describer is responsible for this now) and I also tried to simplify the not supported condition, based on my best understanding of what the old thicket of conditions was doing. You may notice that the internal meta_tensor handling of functional tensor is inconsistent with surrounding code: this is because I *exactly* replicated the old reconstruction behavior; a further refactor would be to rationalize this.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/122202
Approved by: https://github.com/zou3519
Fixes https://github.com/pytorch/pytorch/issues/121085
This PR pretty involved so pay attention to this description. At a high
level, the refactor is intended to be mechanical: anywhere in
MetaConverter where previously we took a Tensor as argument, we now take
a MetaTensorDesc, which contains all of the information that we would
have queried off of the Tensor, but placed into a separate data
structure which we can serialize or use to recreate a fake tensor in
a separate fake tensor mode in exact fidelity to the original.
However, this transformation is not always entirely mechanical. Here
is what you need to pay attention to:
- The memo table from real Tensor -> meta/fake Tensor is now broken
into two memo tables: real Tensor -> stable int id -> meta/fake
Tensor. The stable int id is needed so that when we do serialization,
we know when tensors/storages alias each other and can ensure we preserve
this aliasing upon deserialization.
The way I have implemented changes the weak reference behavior.
Previously, when either the real Tensor OR the meta/fake Tensor went
dead, we would remove the entry from the memo table. Now, this only
removes entries from one of the two memo tables. This semantically
makes sense, because the user may have held on to the stable int id
out of band, and may expect a real Tensor to continue to be numbered
consistently / expect to be able to lookup a meta/fake tensor from
this id. If this is unacceptable, it may be possible to rejigger
the memo tables so that we have real Tensor -> stable int id
and real Tensor -> meta/fake Tensor, but TBH I find the new
implementation a lot simpler, and arranging the memo tables in this
way means that I have to muck around with the real tensor to save
to the memo table; in the current implementation, I never pass the
Tensor to meta_tensor function AT ALL, which means it is impossible
to accidentally depend on it.
- When I fill in the fields of MetaTensorDesc in describe_tensor, I need
to be careful not to poke fields when they are not valid. Previously,
preconditions were implicitly checked via the conditional structure
("is this sparse? is this nested?") that is tested before we start
reading attributes. This structure has to be replicated in
describe_tensor, and I have almost assuredly gotten it wrong on my
first try (I'll be grinding through it on CI; a careful audit will
help too, by auditing that I've tested all the same conditionals that
the original access was guarded by.)
- I originally submitted https://github.com/pytorch/pytorch/pull/121821
for the symbolic shapes change, but it turned out the way I did it
there didn't actually work so well for this PR. I ended up just
inlining the symbolic shapes allocation logic into MetaConverter
(look for calls to maybe_specialize_sym_int_with_hint), maybe there
is a better way to structure it, but what I really want is to
just read sizes/strides/offset directly off of MetaTensorDesc; I
don't want another intermediate data structure.
- Some fields aren't serializable. These are documented as "NOT
serializable". ctx/type should morally be serializable and I just
need to setup a contract with subclasses to let them be serialized.
The fake_mode is used solely to test if we are refakefying with
a pre-existing ShapeEnv and we want to reuse the SymInt
directly--serializing this case is hopeless but I am kind of hoping
after this refactor we do not need this at all. view_func is not
serializable because it's a bound C implemented method. Joel has
promised me that this is not too difficult to actually expose as a
true data structure, but this is the edgiest of edge cases and there
is no reason to deal with it right now.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/122044
Approved by: https://github.com/eellison
List of changes:
- Replace JVP_NESTING by torch._C._functorch.maybe_current_level()
- Remove all increment nesting functions from wrap_fx_proxy_cls
- fwAD.make_dual receives the dual_level as keyword argument
- Add jvp_increment_nesting, set_fwd_grad_enabled and dual_level context managers to dynamo
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119926
Approved by: https://github.com/zou3519
Fixes https://github.com/pytorch/pytorch/issues/121085
This PR pretty involved so pay attention to this description. At a high
level, the refactor is intended to be mechanical: anywhere in
MetaConverter where previously we took a Tensor as argument, we now take
a MetaTensorDesc, which contains all of the information that we would
have queried off of the Tensor, but placed into a separate data
structure which we can serialize or use to recreate a fake tensor in
a separate fake tensor mode in exact fidelity to the original.
However, this transformation is not always entirely mechanical. Here
is what you need to pay attention to:
- The memo table from real Tensor -> meta/fake Tensor is now broken
into two memo tables: real Tensor -> stable int id -> meta/fake
Tensor. The stable int id is needed so that when we do serialization,
we know when tensors/storages alias each other and can ensure we preserve
this aliasing upon deserialization.
The way I have implemented changes the weak reference behavior.
Previously, when either the real Tensor OR the meta/fake Tensor went
dead, we would remove the entry from the memo table. Now, this only
removes entries from one of the two memo tables. This semantically
makes sense, because the user may have held on to the stable int id
out of band, and may expect a real Tensor to continue to be numbered
consistently / expect to be able to lookup a meta/fake tensor from
this id. If this is unacceptable, it may be possible to rejigger
the memo tables so that we have real Tensor -> stable int id
and real Tensor -> meta/fake Tensor, but TBH I find the new
implementation a lot simpler, and arranging the memo tables in this
way means that I have to muck around with the real tensor to save
to the memo table; in the current implementation, I never pass the
Tensor to meta_tensor function AT ALL, which means it is impossible
to accidentally depend on it.
- When I fill in the fields of MetaTensorDesc in describe_tensor, I need
to be careful not to poke fields when they are not valid. Previously,
preconditions were implicitly checked via the conditional structure
("is this sparse? is this nested?") that is tested before we start
reading attributes. This structure has to be replicated in
describe_tensor, and I have almost assuredly gotten it wrong on my
first try (I'll be grinding through it on CI; a careful audit will
help too, by auditing that I've tested all the same conditionals that
the original access was guarded by.)
- I originally submitted https://github.com/pytorch/pytorch/pull/121821
for the symbolic shapes change, but it turned out the way I did it
there didn't actually work so well for this PR. I ended up just
inlining the symbolic shapes allocation logic into MetaConverter
(look for calls to maybe_specialize_sym_int_with_hint), maybe there
is a better way to structure it, but what I really want is to
just read sizes/strides/offset directly off of MetaTensorDesc; I
don't want another intermediate data structure.
- Some fields aren't serializable. These are documented as "NOT
serializable". ctx/type should morally be serializable and I just
need to setup a contract with subclasses to let them be serialized.
The fake_mode is used solely to test if we are refakefying with
a pre-existing ShapeEnv and we want to reuse the SymInt
directly--serializing this case is hopeless but I am kind of hoping
after this refactor we do not need this at all. view_func is not
serializable because it's a bound C implemented method. Joel has
promised me that this is not too difficult to actually expose as a
true data structure, but this is the edgiest of edge cases and there
is no reason to deal with it right now.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/122044
Approved by: https://github.com/eellison
ghstack dependencies: #122018
List of changes:
- Replace JVP_NESTING by torch._C._functorch.maybe_current_level()
- Remove all increment nesting functions from wrap_fx_proxy_cls
- fwAD.make_dual receives the dual_level as keyword argument
- Add jvp_increment_nesting, set_fwd_grad_enabled and dual_level context managers to dynamo
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119926
Approved by: https://github.com/zou3519
List of changes:
- Replace JVP_NESTING by torch._C._functorch.maybe_current_level()
- Remove all increment nesting functions from wrap_fx_proxy_cls
- fwAD.make_dual receives the dual_level as keyword argument
- Add jvp_increment_nesting, set_fwd_grad_enabled and dual_level context managers to dynamo
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119926
Approved by: https://github.com/zou3519
This PR:
* Uses reified ViewFuncs to swap in fake tensors / symbolic SymInts for view replay during subclass view fake-ification
* Enables automatic dynamic on view bases -> fakeifies according to the resultant symbolic context instead of the old "all-static" approach
* Covers the following view types:
* subclass -> dense
* dense -> subclass
* subclass -> subclass
* Dense -> dense views are handled the old way via an `as_strided()` call, as it's likely there is no view func available
Differential Revision: [D54269082](https://our.internmc.facebook.com/intern/diff/D54269082)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/118405
Approved by: https://github.com/ezyang
Decorates all NT tests with `@markDynamoStrictTest` to ensure we get the correct signal. Adds xfails where needed to get things passing.
Includes a fix in meta_utils.py for a bug that was breaking several python 3.11 tests. In particular, a dense tensor graph input that is a view of a strided NT would slip past Dynamo's check and break in meta-ification.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/116111
Approved by: https://github.com/soulitzer, https://github.com/zou3519
ghstack dependencies: #115192
Continuation of #112185, following the design in this [doc](https://docs.google.com/document/d/1ipSxcTzEMMOAPvxP-YJlD5JBZZmIGgh8Q34ixtOUCRo).
Summary:
* Introduce `SubclassSymbolicPolicy` containing separate dynamic dim / constraint policies for the outer and inner tensors
* Expand the automatic dynamic algorithm to recurse into inner tensors and produce one of these for a subclass instance
* Maintain legacy behavior for subclasses by recursively calling `mark_dynamic()` on inner tensors *of the same dim as outer* when `mark_dynamic(outer, ...)` is called
* Addresses this: 6a86cf00ad/torch/_dynamo/variables/builder.py (L1750)
* Add `outer_size` and `outer_stride` arguments to `__tensor_unflatten__()` so that you can find out what symbols were allocated for the outer size / stride (you are expected to return a tensor that compares equal to the outer symbols)
* Signatures now:
```python
# attrs is a list of inner tensor attributes on x; inner_tensor = getattr(x, attr)
# ctx is anything useful for rebuilding the class we want to guard on
attrs, ctx = x.__tensor_flatten__()
...
# inner_tensors is a dict of {attr -> tensor}
# ctx is taken unmodified from flattening and (eventually) guarded on
# outer_size is the expected size of the output; possibly symbolic
# outer_stride is the expected strides of the output; possibly symbolic
y = MySubclass.__tensor_unflatten__(inner_tensors, ctx, outer_size, outer_stride)
# at the __tensor_unflatten__() call-site in PT2, we assert y.shape == outer_size and y.stride() == outer_stride
# the assert simplifies symbols when there are relationships between outer and inner symbols
```
* Size info needed for `NestedTensor` at least, stride info needed for `DTensor` at least
* Punting on `outer_storage_offset` because storage_offset handling is horribly broken in PT2 right now
* ~~Add new `__tensor_mark_dynamic__()` to allow overriding the behavior of mark_dynamic on a per-subclass basis~~ (booted to future work)
* ~~Add guards for tensor subclasses by calling `__tensor_flatten__()` in the guard to test equality on `ctx`~~
* Now handled in #114469
* Next PR: add TENSOR_MATCH guards on inner tensors
Pull Request resolved: https://github.com/pytorch/pytorch/pull/114311
Approved by: https://github.com/ezyang, https://github.com/drisspg, https://github.com/voznesenskym, https://github.com/bdhirsh
Summary:
The primary problem we are setting out to solve here is fake tensor freshness. Before this PR, fake tensors after dynamo represented fake tensors *at the end* of trace, so subsequent retraces like aot_autograd would start off with fake tensors in the wrong (end result) state, rather than their expected fresh state. The solution here is to start a fresh fake mode, and re-fakify the tensors. The nuance comes from ensuring that symbols are uniformly created for the symbolic sizes and strides of the tensor.
This PR is the result of *a lot* of back and forth with ezyang and eellison. Initially, the first pass at this was not super different from what we have in the PR - the broad strokes were the same:
1) We cache source->symbol in shape_env
2) We pass policy objects around, stored at dynamo fakificaiton time, and reused for later fakification
3) We create a new fake mode for backends
(from https://github.com/pytorch/pytorch/pull/113605/files)
This is ugly, and has some layering violations. We detoured our decision making through a few other alternatives. Immutable/mutable fake tensor mode was the most interesting alternative, https://github.com/pytorch/pytorch/pull/113653, and was struck down on concerns of complexity in fake mode combined with it not covering all edge cases. We also detoured on what to do about tensor memoization returning back potentially different tensors than requested, and if that was an anti pattern (it is) we want to hack in with the symbol cache (we don't).
We went back to the drawing board here, but with a few concessions:
1) the cache for source->symbol must live outside of shape_env, for both lifecycle, and layering reasons
2) A good amount of work needs to be done to pipe policy around fake_mode and meta_utils correctly, to cover all the cases (ezyang did this)
cc penguinwu EikanWang jgong5 Guobing-Chen XiaobingSuper zhuhaozhe blzheng wenzhe-nrv jiayisunx chenyang78 aakhundov kadeng
imported-using-ghimport
Test Plan: Imported from OSS
Reviewed By: huydhn, Chillee
Differential Revision: D51566250
Pulled By: voznesenskym
Pull Request resolved: https://github.com/pytorch/pytorch/pull/114526
Approved by: https://github.com/Chillee, https://github.com/huydhn
The primary problem we are setting out to solve here is fake tensor freshness. Before this PR, fake tensors after dynamo represented fake tensors *at the end* of trace, so subsequent retraces like aot_autograd would start off with fake tensors in the wrong (end result) state, rather than their expected fresh state. The solution here is to start a fresh fake mode, and re-fakify the tensors. The nuance comes from ensuring that symbols are uniformly created for the symbolic sizes and strides of the tensor.
This PR is the result of *a lot* of back and forth with @ezyang and @eellison. Initially, the first pass at this was not super different from what we have in the PR - the broad strokes were the same:
1) We cache source->symbol in shape_env
2) We pass policy objects around, stored at dynamo fakificaiton time, and reused for later fakification
3) We create a new fake mode for backends
(from https://github.com/pytorch/pytorch/pull/113605/files)
This is ugly, and has some layering violations. We detoured our decision making through a few other alternatives. Immutable/mutable fake tensor mode was the most interesting alternative, https://github.com/pytorch/pytorch/pull/113653, and was struck down on concerns of complexity in fake mode combined with it not covering all edge cases. We also detoured on what to do about tensor memoization returning back potentially different tensors than requested, and if that was an anti pattern (it is) we want to hack in with the symbol cache (we don't).
We went back to the drawing board here, but with a few concessions:
1) the cache for source->symbol must live outside of shape_env, for both lifecycle, and layering reasons
2) A good amount of work needs to be done to pipe policy around fake_mode and meta_utils correctly, to cover all the cases (@ezyang did this)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/113926
Approved by: https://github.com/ezyang, https://github.com/eellison
Subsumes half of https://github.com/pytorch/pytorch/pull/113605
We support fakeifying an already fake tensor, which will give you a new fake tensor mirroring the same structure as the original fake tensor, which is what is needed by https://github.com/pytorch/pytorch/issues/113643 . However, when this refakeification happens, we will naively reallocate all new sizes for all of the fake tensor. This is the right thing to do if you are re-fakeifying on a fresh ShapeEnv (because you're reparametrizing the sizes or something), but if you have two fake tensor modes which are sharing a shape environment, you would actually rather just reuse the original sizes/strides/offset from the original fake tensor. This ends up being pretty simple. I recommend viewing with whitespace diff turned off.
There's some fuzz around jagged tensor handling; that code is probably not quite right, but I fixed it for this particular case in the most straightforward way.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/113651
Approved by: https://github.com/albanD, https://github.com/eellison, https://github.com/bdhirsh
Currently meta_utils relies on as_strided when handling the view case (recursively meta-ify the base, and then do as_strided to simulate the view), but NestedTensor does not support as_strided today (though maybe it could?), so what we want to do instead is call Tensor. _view_func. Conveniently, _view_func IS always available for nested tensors.
A detail to note is that _view_func actually incurs a guard because it needs to perform some metadata checks to make sure the view is still valid. This PR adds Tensor._unsafe_view_func which can avoid that.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/112205
Approved by: https://github.com/jbschlosser
In this PR:
- Adds support for strides for jagged tensor (design doc for this coming soon)
- NestedTensor skips automatic dynamic
- Make use of @bdhirsh's subclass fakification logic by adding the __tensor_{un,}flatten__ functions.
- Additional logic for fakification: since existing subclass fakification logic does not handle the case where the outer tensor has an additional dimension. We insert one-off logic to (1) insert an extra SingletonSymInt onto the fakified NestedTensor. (2) make sure we call track_symint on both the sizes on the inner and outer tensor during guard creation.
Remaining things that are weird:
- Still need to skip some logic in meta utils for some reason (I was going to write this up more, but decided not to since we're not able to do this anyway for a immediate reason: we cannot arbitrarily compare singleton ints. For now I'm just following Brian's advise from [here](https://github.com/pytorch/pytorch/pull/109171#discussion_r1328137070) )
Pull Request resolved: https://github.com/pytorch/pytorch/pull/109171
Approved by: https://github.com/ezyang, https://github.com/bdhirsh
Reland - the previous PR was reverted by internal with this error:
```
File "/data/sandcastle/boxes/eden-trunk-hg-fbcode-fbsource/buck-out/v2/gen/fbcode/363cd7e240f5d021/caffe2/torch/fb/trainer/data_modules/tests/__test_dataloader__/test_dataloader#link-tree/torch/__init__.py", line 29, in <module>
from ._utils_internal import _functionalize_sync as _sync
ImportError: cannot import name '_functionalize_sync' from 'torch._utils_internal'
```
I couldn't figure out why internal was unhappy with the import. One potential reason is that I see a build rule for *another* `_utils_internal.py` in the fb folder here ([link](https://www.internalfb.com/code/fbsource/[30ed85cd88409af98b7490be137aaa5dfd7afd01]/fbcode/caffe2/TARGETS?lines=444))
Rather than burn more time investigating, I confirmed internally that the error goes away if I move the util from `torch/_utils_internal.py` to `torch/_utils.py`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/109518
Approved by: https://github.com/albanD
Added two new utils to help with turning python functionalization on in AOTAutograd (next PR):
(1) updated `torch._sync()`. Previously, this API could only handle `torch.Tensor` instances that had a `FunctionalTensorWrapper` TensorImpl. It now needs to handle python `FunctionalTensor`'s. In theory I can probably break BC and change this API (since it's private?), but I decided not to do it in this PR stack do minimize the chance of reverts. Instead of updating that API directly (which is in C++), I just added a python shim that first tries to unwrap the python `FunctionalTensor` if there is one, then calls the existing C++ logic
(2) `mirror_autograd_meta` is now a standalone API that tries to mirror the `requires_grad` and `is_leaf` autograd metadata from one tensor to another. Previously this was hardcoded into `torch._to_functional_tensor()`. But I now need to use it in a more standalone way: later in AOTAutograd when we unwrap and re-wrap a tensor subclasses, we need to manually mirror the autograd metadata from the original to the updated version of the subclass.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107917
Approved by: https://github.com/ezyang
ghstack dependencies: #106404
There is already some support for plumbing `__torch_dispatch__` tensor subclasses through dynamo, but this PR beefs it up a bit and adds a test. In particular:
(1) Fakeifying tensor subclasses didn't properly set autograd metadata (requires_grad, is_leaf) on the newly fakeified wrapper subclass. I don't actually have a test for this in this PR, but it's tested pretty heavily later in my aot autograd tests
(2) Fakeifying tensor subclasses didn't properly track source information for dynamic shapes on the inner tensors. I added a new `WrapperSubclassFieldSource` subclass, that represents a source coming from a tensor field on a wrapper subclass, which I use in the fakeifying logic, and again in symbolic_shapes.py to generate proper guards.
(3) `_make_wrapper_subclass()` marginally updated this code to work better with dynamic shapes. One thing that's a bit weird about `_make_wrapper_subclass`: it has two overloads, and the first explicitly does not support dynamic shapes (and the second.. does not support kwargs). I think that later we probably want to consolidate / at least make the first overload work with dynamic shapes, but I didn't want to handle that in this PR (so these smaller changes seemed like a strict improvement).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107415
Approved by: https://github.com/ezyang
This PR allows dynamo to fakify FunctionalTensorWrapper by unwrapping, replacing and wrapping again for FunctionalTensorWrapper so that FunctionalTensorWrapper can be passed in as input for dynamo.optimize and we can support something like this
```python
ff = torch.func.functionalize(f)
torch.compile(ff)(x)
```
This PR didn't follow the \_\_tensor_flatten\_\_ and \_\_tensor_unflatten\_\_ protocol right now because we're not sure the plan of doing that for FunctionalTensorWrapper (it's implemented in C++).
**Test Plan:**
Add a new test.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107062
Approved by: https://github.com/zou3519
ghstack dependencies: #107042
This PR allows dynamo to fakify FunctionalTensorWrapper by unwrapping, replacing and wrapping again for FunctionalTensorWrapper so that FunctionalTensorWrapper can be passed in as input for dynamo.optimize and we can support something like this
```python
ff = torch.func.functionalize(f)
torch.compile(ff)(x)
```
This PR didn't follow the \_\_tensor_flatten\_\_ and \_\_tensor_unflatten\_\_ protocol right now because we're not sure the plan of doing that for FunctionalTensorWrapper (it's implemented in C++).
**Test Plan:**
Add a new test.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107062
Approved by: https://github.com/zou3519
ghstack dependencies: #107042
This PR adds necessary plumbing through torchdynamo to allow tensor
subclasses with certain contract (i.e. with `__tensor_flatten__` and
`__tensor_unflatten__`) to goes through the dynamo fakification pass by
fakifying the tensor subclass internal components.
Some of the tensor subclass contract logic mostly borrowed from
https://github.com/pytorch/pytorch/pull/97540
Added some tests to verify simply passing through a tensor subclass
(i.e. DTensor) through dynamo eager works as expected.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105308
Approved by: https://github.com/ezyang
Add similar semantics for creating a buffer object similar to creating a parameter. This is done by introducing a new `Buffer` class that can be used for type disambiguation. The underlying functionality of registering a buffer remains the same as the `register_buffer` method has not been changed. The `persistent` parameter in the `Buffer` type is to indicate whether a buffer object should be persistent or not. Other non-test changes have to do with getting the new `Buffer` type recognized by inductor and dynamo. Remaining changes are test changes to make sure that the `Buffer` type can be used as a drop in replacement for `register_buffer` as it just leads to `register_buffer` being called. The addition of this new functionality still allows for normal tensors to be used as buffers so these changes are intended to be backwards compatible.
Fixes#35735
Pull Request resolved: https://github.com/pytorch/pytorch/pull/104069
Approved by: https://github.com/mikaylagawarecki
