People access activation checkpoint through many layers of config and it is not always guaranteed that all the layers of wrapping around checkpoint properly propagate all the kwargs, e.g. debug mode. This context manager offers an alternative way to enable debug mode that bypasses the need for all layers to propagate kwargs.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/110728
Approved by: https://github.com/albanD
ghstack dependencies: #110673, #110674, #110675, #110676
This PR implements the feature described in #107036 for `no_grad`, `enable_grad` and `inference_mode`.
Users can still use the above as before but they can also use them without parentheses.
For example:
```python
import torch
a = torch.ones(1, requires_grad=True)
def do_something():
print(2 * a)
with torch.no_grad():
do_something() # tensor([2.])
torch.no_grad()(do_something)() # tensor([2.])
torch.no_grad(do_something)() # tensor([2.])
do_something() # tensor([2.], grad_fn=<MulBackward0>)
```
For `inference_mode`, decorating without parenthesis is equivalent to decorating with the default `mode=True`, similiar to how dataclasses behave (https://docs.python.org/3/library/dataclasses.html#module-contents)
Closes#107036
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107086
Approved by: https://github.com/albanD
Fixes https://github.com/pytorch/pytorch/issues/106754
This PR:
- moves test/autograd/test_fallback.py to test_autograd_fallback.py and
removes it from test_autograd.py (necessary for the next step)
- adds test_autograd_fallback.py to parallel test blocklist.
- lintrunner really wanted to make changes to the files, but other than
that, it is a move.
The problem is that we set a global option (the autograd fallback mode)
during these tests which may cause the tests to interfere with each
other.
Test Plan:
- python test/run_test.py -i test_autograd_fallback
NOTE to diff train oncall:
- You'll also need to modify the test/autograd/test_fallback.py TARGET in
caffe2/test/TARGETS since we renamed the file.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106866
Approved by: https://github.com/soulitzer
Fixes#104985
Implemented `set_multithreading_enabled` C++ function to directly alter state rather than using `MultithreadingEnabled` class, which was automatically resetting the state when the object was destroyed. This behavior more closely aligns with set_grad_enabled which does work as expected. This allows us to change python class `set_multithreading_enabled` to act as both a function and context manager.
I also added a getter: `torch._C.is_multithreading_enabled`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105291
Approved by: https://github.com/albanD
Summary:
Context
-------
This PR adds a new fallback to the Autograd dispatch keys.
If you would prefer the old behavior:
- A quick (unsupported) way to get the previous behavior is to call
`torch._C._set_autograd_fallback("nothing")`
- Register "torch::CppFunction::makeFallthrough()" to your Autograd key,
like in https://gist.github.com/zou3519/d09a5f4b1afe2430af09fea67c6ff2c8
It is possible that this PR regresses performance of overhead-bound
models. If this is the case, please reach out (and apply one of the
temporary fixes in the previous section).
Description for reviewers
-------------------------
In order to deprecate registering autograd kernels at not an autograd
key, we add a fallback to the Autograd dispatch keys. This fallback
raises a warning if the user attempts to backprop through the operator
and is also configurable to either warn or not warn.
The goal of this PR is to
- preserve as much BC as possible
- raise a warning that whatever the user is doing is potentially wrong.
- be as performant as possible
There are roughly two cases:
- if the post-autograd kernels return a Tensor that requires grad, then
we install an autograd hook that raises a warning. We are preserving BC
in that it is possible that the user has a torch::autograd::Function
registered to their CPU key.
- if the post-autograd kernels return Tensors that do not require grad,
then we make them require_grad and install a WarnNotImplemented grad fn
that warns in the backward pass. This is mildy BC-breaking (see next
section).
Test Plan:
- bunch of new tests
BC-Breaking Note
----------------
This PR adds a new fallback to the Autograd dispatch keys. It affects
custom operators that do not have a kernel registered to the Autograd
keys (e.g. AutogradCPU and AutogradCUDA).
If the previous behavior was that the custom operator would return
Tensors that do not require grad if the inputs do require grad, then
this PR changes it so that all floating-point and complex returns do
require grad. See the "Context" section above for how to get the old
behavior.
Differential Revision: D47408353
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105078
Approved by: https://github.com/soulitzer
Context
-------
This PR adds a new fallback to the Autograd dispatch keys.
If you would prefer the old behavior:
- A quick (unsupported) way to get the previous behavior is to call
`torch._C._set_autograd_fallback("nothing")`
- Register "torch::CppFunction::makeFallthrough()" to your Autograd key,
like in https://gist.github.com/zou3519/d09a5f4b1afe2430af09fea67c6ff2c8
It is possible that this PR regresses performance of overhead-bound
models. If this is the case, please reach out (and apply one of the
temporary fixes in the previous section).
Description for reviewers
-------------------------
In order to deprecate registering autograd kernels at not an autograd
key, we add a fallback to the Autograd dispatch keys. This fallback
raises a warning if the user attempts to backprop through the operator
and is also configurable to either warn or not warn.
The goal of this PR is to
- preserve as much BC as possible
- raise a warning that whatever the user is doing is potentially wrong.
- be as performant as possible
There are roughly two cases:
- if the post-autograd kernels return a Tensor that requires grad, then
we install an autograd hook that raises a warning. We are preserving BC
in that it is possible that the user has a torch::autograd::Function
registered to their CPU key.
- if the post-autograd kernels return Tensors that do not require grad,
then we make them require_grad and install a WarnNotImplemented grad fn
that warns in the backward pass. This is mildy BC-breaking (see next
section).
Test Plan:
- bunch of new tests
BC-Breaking Note
----------------
This PR adds a new fallback to the Autograd dispatch keys. It affects
custom operators that do not have a kernel registered to the Autograd
keys (e.g. AutogradCPU and AutogradCUDA).
If the previous behavior was that the custom operator would return
Tensors that do not require grad if the inputs do require grad, then
this PR changes it so that all floating-point and complex returns do
require grad. See the "Context" section above for how to get the old
behavior.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/104481
Approved by: https://github.com/soulitzer
Fixes https://github.com/pytorch/pytorch/issues/104272
This PR adds a new private API `materialize_non_diff_grads` (default True) such that when set to False, grad outputs corresponding to outputs marked non-differentiable would receive None instead of a zero-filled tensor. This is overrides the setting of `materialize_grads`, i.e. grad outputs corresponding non-differentiable outputs would still be None even if `materialize_grads=True` (the default).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/104291
Approved by: https://github.com/albanD
This PR makes some improvements for debuggability of checkpointing:
- improved error messages that are more understandable
- errors are now `CheckpointError` which subclasses `RuntimeError` (only `CheckpointError` triggers debug message, see below)
- stricter error checking by default:
- shapes, dtypes, and device are compared
- we also now error when more tensors are being saved for backward during recompute
- NOTE: checks are relaxed if it is detected that you are doing backward within forward
- shapes, dtype, and device checking can be disabled by passing `determinism_check="none"`
- new debug flag: more helpful error message when `debug=True`
Note:
- cpp stack trace is only included for x86 linux machines
- the error message if cpp stack trace is included can be quite long. For a function checkpointed with 8 operators, the log was around 1300 lines! (should this be hidden behind a flag?)
[Error message when debug='True' (python stack trace only)](https://gist.github.com/soulitzer/3d5e19c7cceae8e22f9bdd625ec39dd4)
[Error message when debug='True' (with python and cpp stacktrace)](https://gist.github.com/soulitzer/ff8fd8c3ccbb2c90dfe3df6d7713b167)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/103859
Approved by: https://github.com/albanD
Now, when you do an inplace mutation and the view is naughty, you get this message:
```
RuntimeError: A view was created in no_grad mode and is being modified inplace with grad mode enabled. Given that this use case is ambiguous and error-prone, it is forbidden. You can clarify your code by moving both the view and the inplace either both inside the no_grad block (if you don't want the inplace to be tracked) or both outside (if you want the inplace to be tracked). To find out where this view was allocated, run your entire forward region under anomaly mode (torch.autograd.detect_anomaly(check_nan=False)).
```
When you run under anomaly mode, you get:
```
RuntimeError: A view was created in no_grad mode and is being modified inplace with grad mode enabled. Given that this use case is ambiguous and error-prone, it is forbidden. You can clarify your code by moving both the view and the inplace either both inside the no_grad block (if you don't want the inplace to be tracked) or both outside (if you want the inplace to be tracked). This view was allocated at:
File "/data/users/ezyang/c/pytorch/test/test_autograd.py", line 4299, in arglebargle
File "/data/users/ezyang/c/pytorch/test/test_autograd.py", line 4306, in test_anomaly_gives_view_stack
File "/home/ezyang/local/c/pytorch-env/lib/python3.10/unittest/case.py", line 549, in _callTestMethod
File "/home/ezyang/local/c/pytorch-env/lib/python3.10/unittest/case.py", line 591, in run
File "/data/users/ezyang/c/pytorch/torch/testing/_internal/common_utils.py", line 2266, in _run_with_retry
File "/data/users/ezyang/c/pytorch/torch/testing/_internal/common_utils.py", line 2337, in run
File "/home/ezyang/local/c/pytorch-env/lib/python3.10/unittest/case.py", line 650, in __call__
File "/home/ezyang/local/c/pytorch-env/lib/python3.10/unittest/suite.py", line 122, in run
File "/home/ezyang/local/c/pytorch-env/lib/python3.10/unittest/suite.py", line 84, in __call__
File "/home/ezyang/local/c/pytorch-env/lib/python3.10/unittest/suite.py", line 122, in run
File "/home/ezyang/local/c/pytorch-env/lib/python3.10/unittest/suite.py", line 84, in __call__
File "/home/ezyang/local/c/pytorch-env/lib/python3.10/unittest/runner.py", line 184, in run
File "/home/ezyang/local/c/pytorch-env/lib/python3.10/unittest/main.py", line 271, in runTests
File "/home/ezyang/local/c/pytorch-env/lib/python3.10/unittest/main.py", line 101, in __init__
File "/data/users/ezyang/c/pytorch/torch/testing/_internal/common_utils.py", line 894, in run_tests
File "/data/users/ezyang/c/pytorch/test/test_autograd.py", line 11209, in <module>
```
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/103185
Approved by: https://github.com/zdevito
Now that we have updated all internal callsites, per https://fb.workplace.com/groups/pytorch.oss.dev/permalink/1635183750239493/ we should raise a warning when use_reentrant is not explicitly passed for 2.1
Deprecation note:
- Not passing in use_reentrant explicitly is now deprecated and will raise a warning. In the future the default value of use-reentrant will be False. To preserve the existing behavior you can pass in use_reentrant=True. It is recommended that you use use_reentrant=False.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/100551
Approved by: https://github.com/Skylion007
Why did I choose context manager instead of per-call? Early stopping is not part of the model definition, and depending on how a particular model is used, e.g., with PT2 or not we may or may not want to disable early stopping.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/96866
Approved by: https://github.com/albanD
Fixes#44189
Adds a new parameter, zero_grad_unused, to the torch.autograd.grad() function. This parameter allows for the gradient to be set to 0 instead of None when a variable is unused, which can be helpful for higher-order partial differentials.
Here is an example of using this new parameter to solve d^3y/dx^3 given y = a * x:
```python
x = torch.tensor(0.5, dtype=torch.float32, requires_grad=True)
a = torch.tensor(1, dtype=torch.float32, requires_grad=True)
y = x * a
dydx = torch.autograd.grad(y, x, create_graph=True, allow_unused=True)
d2ydx2 = torch.autograd.grad(dydx, x, allow_unused=True, zero_grad_unused=True)
try:
d3ydx3 = torch.autograd.grad(d2ydx2, x, allow_unused=True, zero_grad_unused=True)
except RuntimeError as e:
assert False, "Should not raise error"
```
With `zero_grad_unused`, d2ydx2 could be 0 instead of None, enabling d3ydx3 to be calculated as defined in math without throwing an error.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/97015
Approved by: https://github.com/soulitzer
Changes:
- bc-breaking change: The main difference between this and the old non-reentrant impl that it replaces is that we clear recomputed tensors on backward immediately upon unpack, even if retain_graph=True. This has the following additional implications:
- Accessing _saved_tensors multiple times will silently recompute forward multiple times.
- Accessing ctx.saved_tensor twice in the same backward will now raise an error.
- To avoid dealing with the potential consequences, early stopping has been hidden behind a global flag that is by default False, and can be enabled via a context manager. We can remove this in a follow up. Some features of nesting as a result do not work by default.
Before land:
- import to check for more bc-breakingness
- implement any workarounds for the bc-breaking-ness, if we decide on any
- update docs to reflect new lifetime of recomputed variables
- update docs to mention the early stop feature
Follow ups:
- enable early-stopping by default
- update docs/tutorial to feature nested use cases
Related docs:
- code comment: https://github.com/pytorch/pytorch/pull/90105/files#diff-9dcd955620b52ce128e18e3567be88edbb238810460d1288a86fabc20e483b30R448
- design doc: https://docs.google.com/document/d/1UDLhTNv6_kvuDTRlsjfj9WdqtNaQNr8ahrvdBIB6914/edit#
- retains_grad <> checkpiont https://docs.google.com/document/d/1maiGmuFUxysQL0AdYUU88kngAaXh_L0XpDcLDh_5Ors/edit
Pull Request resolved: https://github.com/pytorch/pytorch/pull/90105
Approved by: https://github.com/albanD
