**Background**: "TorchDynamo Cache Lookup" events appear in traces to indicate a dynamo cache lookup; it's useful to check when cache lookups are taking a long time. To add a profiler event, one can use the `torch.profiler.record_function` context manager, or the C++ equivalent. Previously, the python version was used; first, when the profiler was enabled, callbacks for record_function_enter and record_function_exit were registered; then those would be called before and after every cache lookup.
**This PR**: Instead of calling the python bindings for `torch.profiler.record_function`, directly call the C++ implementation. This simplifies a lot of the code for binding C/C++. It also improves performance; previously there was a lot of overhead in the "TorchDynamo Cache Lookup" event, making the event artificially take a long time. After this change the events now appear shorter, because there's less overhead in starting/stopping the event: in other words, the profiler no longer distorts the results as much.
**Performance results**:
I ran using the script below on a cpu-only 1.6GHz machine. I report the median time (from 100 measurements) of a "TorchDynamo Cache Lookup" event before and after this PR. I think it is reasonable to consider the difference to be due to a reduction in overhead.
<details>
<summary>Benchmarking script</summary>
```python
def fn(x, y):
return (x * y).relu()
a, b = [torch.rand((4, 4), requires_grad=True) for _ in range(2)]
opt_fn = torch.compile(fn)
opt_fn(a, b)
opt_fn(a, b)
with torch.profiler.profile() as prof:
opt_fn(a, b)
```
</details>
Median before PR: 198-228 us (median of 100, measured 5 times)
Median after PR: 27us
Pull Request resolved: https://github.com/pytorch/pytorch/pull/108436
Approved by: https://github.com/anijain2305, https://github.com/jansel
Adds a profiler start and end callback to dynamo's C eval_frame impl, which can be used to profile a region providing a name for visualization. Currently only hooks up one usage to profile cache lookup (primarily covering guards and linear search through linked list).
Example profile taken from toy model:
`python benchmarks/dynamo/distributed.py --toy_model --profile --dynamo aot_eager`
<img width="1342" alt="image" src="https://user-images.githubusercontent.com/4984825/223225931-b2f6c5a7-505a-4c90-9a03-34982f6dc033.png">
Planning to measure overhead in CI, and probably can't afford to check this in enabled by default. Will have to evaluate UX options such as `config.profile_dynamo_cache = True` or some other way.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/96119
Approved by: https://github.com/jansel
Changes:
- #95200
1. Recognize `.py.in` and `.pyi.in` files as Python in VS Code for a better development experience.
2. Fix deep setting merge in `tools/vscode_settings.py`.
- #95267
3. Use `Namedtuple` rather than `namedtuple + __annotations__` for `torch.nn.utils.rnn.PackedSequence_`:
`namedtuple + __annotations__`:
```python
PackedSequence_ = namedtuple('PackedSequence_',
['data', 'batch_sizes', 'sorted_indices', 'unsorted_indices'])
# type annotation for PackedSequence_ to make it compatible with TorchScript
PackedSequence_.__annotations__ = {'data': torch.Tensor, 'batch_sizes': torch.Tensor,
'sorted_indices': Optional[torch.Tensor],
'unsorted_indices': Optional[torch.Tensor]}
```
`Namedtuple`: Python 3.6+
```python
class PackedSequence_(NamedTuple):
data: torch.Tensor
batch_sizes: torch.Tensor
sorted_indices: Optional[torch.Tensor]
unsorted_indices: Optional[torch.Tensor]
```
- => this PR: #95268
4. Sort import statements and remove unnecessary imports in `.pyi`, `.pyi.in` files.
5. Format `.pyi`, `.pyi.in` files and remove unnecessary ellipsis `...` in type stubs.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/95268
Approved by: https://github.com/huydhn
It's kind of intractable to enable mypy everywhere at the moment,
because there are a lot of errors, and also mypy is really slow
for some reason. I just want enough types to explain the public
types for user compiler calls, going through typing the _C.dynamo
bindings along the way. This is a first step for this.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/89731
Approved by: https://github.com/suo
