[RFC][Codegen] Add custom namespace support (#78015)

Summary:
Adding a feature to allow user to specify namespaces for operator and kernels.

# Feature
There's a feature request to allow DSL to:
1. take in an operator namespace other than `aten`.
2. take in a kernel that is in a different namespace than `at::native`.

For both features, we only allow user to have a single layer of namespace for the sake of simplicity. If user specify `custom::function` as kernel, the codegen will depend on `custom::native::function` where `native` is hardcoded.

# Proposal

For feature 1, add a `namespace` attribute to data class `NativeFunction`. The namespace will be extract out by matching pattern "::" on the `func` variable. For `NativeFunctionsGroup` there's an assumption that all variants (function, inplace, out) will have the same namespace. By default (if not specified) the namespace will be "aten".

For feature 2, add a `namespace` attribute to `BackendMetadata` class, similarly match pattern "::" on the kernel field. Remove the `cpp_namespace` field from `register_dispatch_key` data class. By default (if not specified) the namespace for a kernel would be "at::native".

Test Plan:
Example yaml entries:
```
- func: custom::gelu.out(Tensor self, *, str approximate='none', Tensor(a!) out) -> Tensor(a!)
  structured: True
  structured_inherits: TensorIteratorBase
  device_check: NoCheck   # TensorIterator
  python_module: nn
  dispatch:
    CPU: custom::gelu_out_cpu
    CUDA: custom::gelu_out_cuda
    MPS: custom::gelu_out_mps

- func: custom::gelu_(Tensor(a!) self, *, str approximate='none') -> Tensor(a!)
  structured_delegate: gelu.out
  device_check: NoCheck   # TensorIterator
  python_module: nn
  dispatch:
    NestedTensorCPU, NestedTensorCUDA: custom::NestedTensor_gelu_

- func: custom::gelu(Tensor self, *, str approximate='none') -> Tensor
  structured_delegate: gelu.out
  device_check: NoCheck   # TensorIterator
  python_module: nn
  dispatch:
    MkldnnCPU: custom::mkldnn_gelu
    QuantizedCPU: custom::gelu_quantized_cpu
    NestedTensorCPU, NestedTensorCUDA: custom::NestedTensor_gelu
```

see generated code:

`RegisterCPU.cpp`:
```
TORCH_LIBRARY_IMPL(aten, CPU, m) {
  ...
}
TORCH_LIBRARY_IMPL(custom, CPU, m) {
    m.impl("gelu", TORCH_FN(wrapper_gelu));
    m.impl("gelu.out", TORCH_FN(wrapper_gelu_out_out));
    m.impl("gelu_", TORCH_FN(wrapper_gelu_));
};
```
```
struct structured_gelu_out_cpu_inplace final : public custom::native::structured_gelu_out_cpu {
    structured_gelu_out_cpu_inplace(Tensor& self) : outputs_{std::ref(self)} {}

    void set_output_strided(
        int64_t output_idx, IntArrayRef sizes, IntArrayRef strides,
        TensorOptions options, DimnameList names
    ) override {

        const auto& out = outputs_[output_idx].get();
        check_inplace(out, sizes, options);

        auto maybe_proxy = maybe_create_proxy(out, sizes, strides, options);
        if (C10_UNLIKELY(maybe_proxy.has_value())) {
            proxy_outputs_[output_idx] = c10::ExclusivelyOwned<Tensor>(std::move(maybe_proxy).value());
        }

        if (!names.empty()) {
          namedinference::propagate_names(outputs_[output_idx], names);
        }
        // super must happen after, so that downstream can use maybe_get_output
        // to retrieve the output
        custom::native::structured_gelu_out_cpu::set_output_raw_strided(output_idx, sizes, strides, options, names);
    }

    void set_output_raw_strided(
        int64_t output_idx, IntArrayRef sizes, IntArrayRef strides,
        TensorOptions options, DimnameList names
    ) override {

        const auto& out = outputs_[output_idx].get();
        check_inplace(out, sizes, options);

        if (!names.empty()) {
          namedinference::propagate_names(outputs_[output_idx], names);
        }
        // super must happen after, so that downstream can use maybe_get_output
        // to retrieve the output
        custom::native::structured_gelu_out_cpu::set_output_raw_strided(output_idx, sizes, strides, options, names);
    }

    const Tensor& maybe_get_output(int64_t output_idx) override {
      return proxy_outputs_[output_idx].has_value() ? **proxy_outputs_[output_idx] : outputs_[output_idx].get();

    }
    std::array<std::reference_wrapper<Tensor>, 1> outputs_;
    std::array<c10::optional<c10::ExclusivelyOwned<Tensor>>, 1> proxy_outputs_;
};
```

`RegisterSchema.cpp`
```
TORCH_LIBRARY(aten, m) {
  ...
}
TORCH_LIBRARY(custom, m) {
    m.def("gelu.out(Tensor self, *, str approximate='none', Tensor(a!) out) -> Tensor(a!)");

    m.def("gelu_(Tensor(a!) self, *, str approximate='none') -> Tensor(a!)");

    m.def("gelu(Tensor self, *, str approximate='none') -> Tensor");
};
```

Differential Revision: D36558459

Pull Request resolved: https://github.com/pytorch/pytorch/pull/78015
Approved by: https://github.com/bdhirsh
This commit is contained in:
Mengwei Liu
2022-06-10 21:04:36 +00:00
committed by PyTorch MergeBot
parent d28e9e145b
commit 24050a5801
7 changed files with 142 additions and 87 deletions

View File

@ -123,7 +123,9 @@ Only the following keys are supported: {", ".join(valid_keys)}'
# See Note [External Backends Follow Dispatcher API]
kernel_name = dispatcher.name(native_functions_map[op_name].func)
# TODO: allow structured external backends later.
m = BackendMetadata(kernel=kernel_name, structured=False)
m = BackendMetadata(
kernel=kernel_name, structured=False, cpp_namespace=cpp_namespace
)
metadata[op_name] = m
return BackendIndex(
dispatch_key=dispatch_key,
@ -373,7 +375,6 @@ def gen_dispatcher_registrations(
fm: FileManager,
output_dir: str,
class_name: str,
cpp_namespace: str,
backend_indices: Dict[DispatchKey, BackendIndex],
grouped_native_functions: Sequence[Union[NativeFunction, NativeFunctionsGroup]],
backend_dispatch_key: DispatchKey,
@ -403,7 +404,6 @@ def gen_dispatcher_registrations(
Target.REGISTRATION,
selector,
rocm=False,
cpp_namespace=cpp_namespace,
class_method_name=f"{class_name}",
skip_dispatcher_op_registration=False,
),
@ -462,7 +462,6 @@ TORCH_API void Register${backend_name}${dispatch_key}NativeFunctions() {
Target.ANONYMOUS_DEFINITION,
selector,
rocm=False,
cpp_namespace=cpp_namespace,
class_method_name=f"{class_name}",
skip_dispatcher_op_registration=False,
),
@ -548,7 +547,6 @@ def run(
fm,
output_dir,
class_name,
cpp_namespace,
backend_indices,
grouped_native_functions,
backend_key,