Shortcuts

Source code for torch.cuda.streams

# mypy: allow-untyped-defs
import ctypes

import torch
from torch._streambase import _EventBase, _StreamBase
from .._utils import _dummy_type


if not hasattr(torch._C, "_CudaStreamBase"):
    # Define dummy base classes
    torch._C.__dict__["_CudaStreamBase"] = _dummy_type("_CudaStreamBase")
    torch._C.__dict__["_CudaEventBase"] = _dummy_type("_CudaEventBase")


[docs]class Stream(torch._C._CudaStreamBase, _StreamBase): r"""Wrapper around a CUDA stream. A CUDA stream is a linear sequence of execution that belongs to a specific device, independent from other streams. See :ref:`cuda-semantics` for details. Args: device(torch.device or int, optional): a device on which to allocate the stream. If :attr:`device` is ``None`` (default) or a negative integer, this will use the current device. priority(int, optional): priority of the stream, should be 0 or negative, where negative numbers indicate higher priority. By default, streams have priority 0. """ def __new__(cls, device=None, priority=0, **kwargs): # setting device manager is expensive, so we avoid it unless necessary if device is None or ("stream_id" in kwargs and "device_index" in kwargs): return super().__new__(cls, priority=priority, **kwargs) else: with torch.cuda.device(device): return super().__new__(cls, priority=priority, **kwargs)
[docs] def wait_event(self, event) -> None: r"""Make all future work submitted to the stream wait for an event. Args: event (torch.cuda.Event): an event to wait for. .. note:: This is a wrapper around ``cudaStreamWaitEvent()``: see `CUDA Stream documentation`_ for more info. This function returns without waiting for :attr:`event`: only future operations are affected. .. _CUDA Stream documentation: https://docs.nvidia.com/cuda/cuda-runtime-api/group__CUDART__STREAM.html """ event.wait(self)
[docs] def wait_stream(self, stream) -> None: r"""Synchronize with another stream. All future work submitted to this stream will wait until all kernels submitted to a given stream at the time of call complete. Args: stream (Stream): a stream to synchronize. .. note:: This function returns without waiting for currently enqueued kernels in :attr:`stream`: only future operations are affected. """ self.wait_event(stream.record_event())
[docs] def record_event(self, event=None): r"""Record an event. Args: event (torch.cuda.Event, optional): event to record. If not given, a new one will be allocated. Returns: Recorded event. """ if event is None: event = Event() event.record(self) return event
[docs] def query(self) -> bool: r"""Check if all the work submitted has been completed. Returns: A boolean indicating if all kernels in this stream are completed. """ return super().query()
[docs] def synchronize(self) -> None: r"""Wait for all the kernels in this stream to complete. .. note:: This is a wrapper around ``cudaStreamSynchronize()``: see `CUDA Stream documentation`_ for more info. """ super().synchronize()
@property def _as_parameter_(self): return ctypes.c_void_p(self.cuda_stream) def __eq__(self, o) -> bool: if isinstance(o, Stream): return super().__eq__(o) return False def __hash__(self): return hash((self.cuda_stream, self.device)) def __repr__(self): return f"<torch.cuda.Stream device={self.device} cuda_stream={self.cuda_stream:#x}>"
[docs]class ExternalStream(Stream): r"""Wrapper around an externally allocated CUDA stream. This class is used to wrap streams allocated in other libraries in order to facilitate data exchange and multi-library interactions. .. note:: This class doesn't manage the stream life-cycle, it is the user responsibility to keep the referenced stream alive while this class is being used. Args: stream_ptr(int): Integer representation of the `cudaStream_t` value. allocated externally. device(torch.device or int, optional): the device where the stream was originally allocated. If device is specified incorrectly, subsequent launches using this stream may fail. """ def __new__(cls, stream_ptr, device=None, **kwargs): with torch.cuda.device(device): return super().__new__(cls, stream_ptr=stream_ptr, **kwargs)
[docs]class Event(torch._C._CudaEventBase, _EventBase): r"""Wrapper around a CUDA event. CUDA events are synchronization markers that can be used to monitor the device's progress, to accurately measure timing, and to synchronize CUDA streams. The underlying CUDA events are lazily initialized when the event is first recorded or exported to another process. After creation, only streams on the same device may record the event. However, streams on any device can wait on the event. Args: enable_timing (bool, optional): indicates if the event should measure time (default: ``False``) blocking (bool, optional): if ``True``, :meth:`wait` will be blocking (default: ``False``) interprocess (bool): if ``True``, the event can be shared between processes (default: ``False``) .. _CUDA Event Documentation: https://docs.nvidia.com/cuda/cuda-runtime-api/group__CUDART__EVENT.html """ def __new__(cls, enable_timing=False, blocking=False, interprocess=False): return super().__new__( cls, enable_timing=enable_timing, blocking=blocking, interprocess=interprocess, )
[docs] @classmethod def from_ipc_handle(cls, device, handle): r"""Reconstruct an event from an IPC handle on the given device.""" return super().from_ipc_handle(device, handle)
[docs] def record(self, stream=None): r"""Record the event in a given stream. Uses ``torch.cuda.current_stream()`` if no stream is specified. The stream's device must match the event's device. """ if stream is None: stream = torch.cuda.current_stream() super().record(stream)
[docs] def wait(self, stream=None) -> None: r"""Make all future work submitted to the given stream wait for this event. Use ``torch.cuda.current_stream()`` if no stream is specified. .. note:: This is a wrapper around ``cudaStreamWaitEvent()``: see `CUDA Event documentation`_ for more info. """ if stream is None: stream = torch.cuda.current_stream() super().wait(stream)
[docs] def query(self): r"""Check if all work currently captured by event has completed. Returns: A boolean indicating if all work currently captured by event has completed. """ return super().query()
[docs] def elapsed_time(self, end_event): r"""Return the time elapsed. Time reported in milliseconds after the event was recorded and before the end_event was recorded. """ return super().elapsed_time(end_event)
[docs] def synchronize(self) -> None: r"""Wait for the event to complete. Waits until the completion of all work currently captured in this event. This prevents the CPU thread from proceeding until the event completes. .. note:: This is a wrapper around ``cudaEventSynchronize()``: see `CUDA Event documentation`_ for more info. """ super().synchronize()
[docs] def ipc_handle(self): r"""Return an IPC handle of this event. If not recorded yet, the event will use the current device. """ return super().ipc_handle()
@property def _as_parameter_(self): return ctypes.c_void_p(self.cuda_event) def __repr__(self) -> str: if self.cuda_event: return f"<torch.cuda.Event {self._as_parameter_.value:#x}>" else: return "<torch.cuda.Event uninitialized>"

Docs

Access comprehensive developer documentation for PyTorch

View Docs

Tutorials

Get in-depth tutorials for beginners and advanced developers

View Tutorials

Resources

Find development resources and get your questions answered

View Resources