This diff intends to build device generic torch.Stream and torch.Event for newly added accelerators in PyTorch.
------------
**torch.Stream APIs**
```
# Defined in torch/csrc/Stream.cpp
class Stream(_StreamBase):
stream_id: _int # Stream id
device_index: _int
device_type: _int
device: _device # The device of the stream
@overload
def __new__(self, device: Optional[DeviceLikeType] = None, priority: _int = 0) -> Stream: ...
@overload
def __new__(self, stream_id: _int, device_index: _int, device_type: _int, priority: _int = 0) -> Stream: ...
def query(self) -> _bool: ...
def synchronize(self) -> None: ...
def wait_event(self, event: Event) -> None: ...
def wait_stream(self, other: Stream) -> None: ...
def record_event(self, event: Optional[Event] = None) -> Event: ...
def query(self) -> None: ...
def synchronize(self) -> None: ...
def __hash__(self) -> _int: ...
def __repr__(self) -> str: ...
def __eq__(self, other: object) -> _bool: ...
```
------------------
**torch.Event APIs**:
- IPC related APIs are not implemented, since many device backends don't support it, but we leave interfaces there for future adaption of torch.cuda.Stream.
- currently only the enable_timing is supported, since it is the most common one used in other device backends. We have to refactor the event flag system in PyTorch to support more fancy flag.
- elapsedTime API is added to c10::Event
```
# Defined in torch/csrc/Event.cpp
class Event(_EventBase):
device: _device # The device of the Event
event_id: _int # The raw event created by device backend
def __new__(self,
device: Optional[DeviceLikeType] = None,
enable_timing: _bool = False,
blocking: _bool = False,
interprocess: _bool = False) -> Event: ...
@classmethod
def from_ipc_handle(self, device: DeviceLikeType, ipc_handle: bytes) -> Event: ...
def record(self, stream: Optional[Stream] = None) -> None: ...
def wait(self, stream: Optional[Stream] = None) -> None: ...
def query(self) -> _bool: ...
def elapsed_time(self, other: Event) -> _float: ...
def synchronize(self) -> None: ...
def ipc_handle(self) -> bytes: ...
def __repr__(self) -> str: ...
```
-----------
c10::Event provides new APIs
- calculate **elapsedTime**.
- Get raw event id
- Synchronize event.
```
double elapsedTime(const Event& event) const {
return impl_.elapsedTime(event.impl_);
}
void* eventId() const {
return impl_.eventId();
}
void synchronize() const {
return impl_.synchronize();
}
```
----------
TODO: need to find a good way to test them in PyTorch with API mocks.
Differential Revision: [D55351839](https://our.internmc.facebook.com/intern/diff/D55351839/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/123611
Approved by: https://github.com/albanD
