PoC demonstrating vmap + NT based on the [design doc](https://docs.google.com/document/d/1dVVk6TOqz93PLTIneU2T3xaxCs9qZ0MaJyCvOAp_bC0). This PR:
* Allows `BatchedTensorImpl`s to contain NTs
* Introduces a `BatchedNestedTensor` dispatch key for NT-specific batching rules
* Provides a batching rule fallback that unbinds the NTs -> performs computation on constituent -> rebinds results into NT
Restrictions:
* Only supports one level of vmap
* Only supports vmapping over dim=0 for NTs
* For operations with mixed NT / dense inputs, support is also limited to dim=0 for the dense inputs
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106786
Approved by: https://github.com/zou3519
As part of this, a new `AutocastIPU` dispatch key has been added.
There's an existing PR, #85043, to make `Autocast` a proper per-backend functionality key, but it ran into issues with layering with other functionality keys and went stale.
This has been tested in the out-of-tree IPU PyTorch backend.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/103890
Approved by: https://github.com/albanD
We discussed in a composability meeting a few weeks ago that `pre_autograd` should probably be renamed to `pre_dispatch`.
One question in this PR was: should I re-use a dispatch key? Or should I create a new dispatch key (that yet again corresponds to "top of the dispatcher")?
~~For now, I ended up sticking our proxy mode on the mode stack corresponding to `PythonTLSSnapshot`, because it was simple and it works. It looks like one of the functorch dispatch keys has higher priority though, so it's possible that functorch will end up running first. Open to options, but we can consider adding a new dispatch key later if that becomes a problem~~
Update: I added a dedicated dispatch key, `PreDispatch`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/101818
Approved by: https://github.com/ezyang, https://github.com/Neilblaze, https://github.com/albanD, https://github.com/zou3519
Fixes #ISSUE_NUMBER
1、add amp support for custom backend
2、optimize the file `backend_registration.py`, and rename it with `custom_backend_registration.py`. And then we would register other funcs for custom backend.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/96188
Approved by: https://github.com/bdhirsh
Fixes #ISSUE_NUMBER
1、add amp support for custom backend
2、optimize the file `backend_registration.py`, and rename it with `custom_backend_registration.py`. And then we would register other funcs for custom backend.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/96188
Approved by: https://github.com/bdhirsh
The other `Autograd[Backend]` keys all have fallthrough kernels registered to them, but `AutogradMeta` was missing the fallthrough kernel.
This is a problem for custom ops that don't have autograd support, if you try to run them with meta tensors. If you have a custom op, and register a CPU and a Meta kernel, then:
(1) if you run the op with cpu tensors, it will dispatch straight to the CPU kernel (as expected)
(2) if you run the op with meta tensors, you will error - because we don't have a fallthrough registered to the AutogradMeta key, we will try to dispatch to the AutogradMeta key and error, since the op author hasn't provided an autograd implementation.
Here's a repro that I confirmed now works:
```
import torch
from torch._dispatch.python import enable_python_dispatcher
from torch._subclasses.fake_tensor import FakeTensorMode
lib = torch.library.Library("test", "DEF")
impl_cpu = torch.library.Library("test", "IMPL", "CPU")
impl_meta = torch.library.Library("test", "IMPL", "Meta")
def foo_impl(x):
return x + 1
lib.define("foo(Tensor a) -> Tensor")
impl_meta.impl("foo", foo_impl)
impl_cpu.impl("foo", foo_impl)
with enable_python_dispatcher():
a = torch.ones(2, device='meta')
print("@@@@@")
b = torch.ops.test.foo.default(a)
print(b)
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/94603
Approved by: https://github.com/ezyang, https://github.com/albanD
Summary: This adds a new MTIA DeviceType which is associated with the MTIA DispatchKey and will be used for the Meta in-house training and inference accelerators.
Test Plan: All CI should pass.
Differential Revision: D42526044
Pull Request resolved: https://github.com/pytorch/pytorch/pull/92232
Approved by: https://github.com/ezyang
Signed-off-by: Edward Z. Yang <ezyangfb.com>
From @ezyang's original PR:
There are a number of situations where we have non-backend kernels (e.g., CompositeImplicitAutograd, batching rules) which we would like to port to Python, but we have no way to integrate these ports with the overall system while using preexisting C++ registrations otherwise. This PR changes that by introducing a Python dispatcher (which can have its own kernels directly in Python), which can be interpose over ordinary C++ dispatch. The ingredients:
We introduce a new PythonDispatcher dispatch key, that has the same tenor as FuncTorchDynamicLayerFrontMode: it works by getting triggered before every other dispatch key in the dispatch key, and shunting to a Python implementation
The Python dispatcher is a per-interpreter global object that is enabled/disabled via the guard EnablePythonDispatcher/DisablePythonDispatcher. We don't make it compositional as I have no idea what a compositional version of this feature would look like. Because it is global, we don't need to memory manage it and so I use a simpler SafePyHandle (newly added) to control access to this pointer from non-Python C++. Like __torch_dispatch__, we use PyInterpreter to get to the Python interpreter to handle the dispatch.
I need to reimplement dispatch table computation logic in Python. To do this, I expose a lot more helper functions for doing computations on alias dispatch keys and similar. I also improve the pybind11 handling for DispatchKey so that you can either accept the pybind11 bound enum or a string; this simplifies our binding code. See https://github.com/pybind/pybind11/issues/483#issuecomment-1237418106 for how this works; the technique is generally useful.
I need to be able to call backend fallbacks. I do this by permitting you to call at a dispatch key which doesn't have a kernel for the operator; if the kernel doesn't exist, we check the backend fallback table instead.
Signed-off-by: Edward Z. Yang <ezyang@fb.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/84826
Approved by: https://github.com/ezyang
From PR:
```
Note: [Fake Tensor Dispatch Keys]
In order to model the behavior of device-specific autocast
and autograd logic, we update the dispatch keys of FakeTensors
to reflect their fake device. This includes the BackendComponent
(DispatchKey::Meta -> DispatchKey::CUDA), and also the BackendComponent
related Autocast and Autograd keys. __torch__dispatch__ sits below
Autocast and Autograd, and is only invoked when we are at the
kernel for the BackendComponent. Then, we add Meta to the
thread-local dispatch include set to hit the meta kernel
instead of the kernel of the BackendComponent for the fake device.
```
Also adds the `conv1/2/3d.padding` operators to the Autocast rule set. Without that fix, the FakeTensor dtype would diverge.
See: https://github.com/pytorch/pytorch/issues/81608
Pull Request resolved: https://github.com/pytorch/pytorch/pull/82449
Approved by: https://github.com/ezyang
Seems like it should be one. This will make it possible to register
meta implementations even when there is a CompositeImplicitAutograd
registration already. It also paves the way for sparse meta, etc.
Signed-off-by: Edward Z. Yang <ezyangfb.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/78469
Approved by: https://github.com/ngimel
