Fixes https://github.com/pytorch/pytorch/issues/121353
our handle for `.data` in dynamo today basically just converts `y = x.data` into `y = x.detach()`. The semantics of these two ops are not quite the same, because:
(1) any future mutations on `x.data` will be fully ignored by autograd
(2) any mutations on `x.detach()` will bump x's version counter
the linked model does a .data mutation that is hidden from autograd in eager, but ends up erroring during AOTDispatcher tracing.
I updated dynamo's handling so that:
(1) when dynamo sees a call to `getattr(tensor, "data")` and calls `.detach()` we set a flag on the returned `TensorVariable` indicating it came from `.data`
(2) on any tensor method that we call with an input `TensorVariable` with this flag turned on, we proxy autograd's `preserve_version_counter` logic into the graph, to properly reset the VC after the op is run.
One thing to note is that I don't actually do this on every op that we pass the tensor to: I only do it for tensor methods that appear to be mutations (by checking for a trailing underscore). My thought was that:
(1) I didn't want to do this for **every** op that you pass `y` into, since that will e.g. triple the number of nodes in the graph, and could cause compile time regressions if you use .data
(2) this situation is pretty rare in general, and I'm hoping that "tensor method mutations" cover most reasonable mutation cases. If we manage to miss a case, you will get a loud error during tracing anyway, so there is not a safety issue.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131403
Approved by: https://github.com/anijain2305, https://github.com/zou3519
Fixes https://github.com/pytorch/pytorch/issues/130750.
Repro of lazy/eager `map` discrepancy without `islice`:
```python
def fn(a, b):
y = 1
def f(x):
nonlocal y
y += 1
return x
l = list(zip([a, b], map(f, [1, 2, 3, 4])))
return a + y
```
The major change is that we implement `MapVariable` and `ZipVariable` based on `IteratorVariable`. Before, `map` and `zip` were being traced by immediately unpacking the result as a `TupleVariable`, which is wrong in cases such as the example above.
`MapVariable`s are not allowed to be unpacked while `ZipVariable`s can only be unpacked if all of its iterables can also be unpacked.
We also add new `[has_]force_unpack_var_sequence` methods to `VariableTracker` for the case where it is safe to unpack the entire sequence lazily, e.g., when building a list from a map (i.e. `list(map(f, ...))`).
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131413
Approved by: https://github.com/anijain2305
Fixes https://github.com/pytorch/pytorch/issues/103602.
This PR implements the idea of "if someone creates a string and then ends up not using it, we would prefer to NOT have specialized." mentioned in above issue. Specifically, we create a lazy variable tracker instead of ConstantVariable when we're in FORMAT_VALUE, and when the lazy variable tracker is realized (i.e. it's going to be used), we create a ConstantVariable and the specialization/guarding happens at the time of realization.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131529
Approved by: https://github.com/ezyang
This PR implements an opt-in configuration option for synchronizing compilation across all ranks at the end of Dynamo tracing (and potentially, other places in the future). There are two pieces to this PR:
1. Implementing infrastructure for compiler collectives (DistributedState/LocalState, the actual collective)
2. Using this infrastructure to synchronize automatic dynamic choices across all ranks
The infrastructure in part one can be used for other purposes, just add more (serializable) fields to LocalState.
Here is how automatic dynamic synchronization works:
1. Preflight in "torch/_dynamo/variables/builder.py": On the first Dynamo trace run, we trace without automatic dynamic at all; we assume all Tensor inputs that are not otherwise marked are static. This run is purely to collect all Tensor input sizes in the program.
2. torch/_dynamo/output_graph.py: At the end of the first Dynamo trace run, we perform a compiler collective to distribute all Tensor input sizes to all ranks. Then, we restart Dynamo
3. Apply the updates in "torch/_dynamo/variables/builder.py": Now that we have all sizes for every rank, we now update frame state with the observed sizes for all ranks, in rank order. Under the assumption that frame state is consistent on all ranks, this series of updates will preserve consistency.
For future work, it would be safer if we force a consistent hint on all ranks; this is more involved as we have to interpose in fakification.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/130935
Approved by: https://github.com/jansel
The issue addressed is that compiled autograd changes the calling convention of the FX graph to only have a single placeholder which contains a list of inputs. In this case, the meta of the tensor input nodes don't contain the `tensor_dict` meta. This adds them.
The context is that `tensor_dict` is used to convey if a tensor is an input with a static address.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131556
Approved by: https://github.com/anijain2305
Summary:
- Log export errors to Scuba and mark them with "classified" and "unclassified"
- Classify errors by exception type (ALLOW_LIST) and a `case_name` attribute
- Add `case_name` for some exceptions.
Test Plan:
Running the code below logs a classified error to `torch_export_usage` table in Scuba.
```
import torch
from torch._export.db.case import SupportLevel
class TorchSymMin(torch.nn.Module):
"""
torch.sym_min operator is not supported in export.
"""
def forward(self, x):
return x.sum() + torch.sym_min(x.size(0), 100)
example_args = (torch.randn(3, 2),)
tags = {"torch.operator"}
support_level = SupportLevel.NOT_SUPPORTED_YET
model = TorchSymMin()
torch.export.export(model, example_args)
``
Differential Revision: D59981459
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131327
Approved by: https://github.com/zhxchen17
All the changes brought by the original PR have been addressed in alternative ways in the stack. Why the original PR has to be reverted requires more effort because there is some bad interaction with export.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131058
Approved by: https://github.com/williamwen42
