cupy.cuda.ExternalStream

class cupy.cuda.ExternalStream(ptr)

CUDA stream.

This class allows to use external streams in CuPy by providing the stream pointer obtained from the CUDA runtime call. The user is in charge of managing the life-cycle of the stream.

Parameters

ptr (intptr_t) – Address of the cudaStream_t object.

Variables

ptr (intptr_t) – Raw stream handle. It can be passed to the CUDA Runtime API via ctypes.

Methods

__enter__(self)
__exit__(self, *args)
add_callback(self, callback, arg)

Adds a callback that is called when all queued work is done.

Parameters
  • callback (function) – Callback function. It must take three arguments (Stream object, int error status, and user data object), and returns nothing.

  • arg (object) – Argument to the callback.

Note

Whenever possible, use the launch_host_func() method instead of this one, as it may be deprecated and removed from CUDA at some point.

launch_host_func(self, callback, arg)

Launch a callback on host when all queued work is done.

Parameters
  • callback (function) – Callback function. It must take only one argument (user data object), and returns nothing.

  • arg (object) – Argument to the callback.

Note

Whenever possible, this method is recommended over add_callback(), which may be deprecated and removed from CUDA at some point.

record(self, event=None)

Records an event on the stream.

Parameters

event (None or cupy.cuda.Event) – CUDA event. If None, then a new plain event is created and used.

Returns

The recorded event.

Return type

cupy.cuda.Event

synchronize(self)

Waits for the stream completing all queued work.

use(self)

Makes this stream current.

If you want to switch a stream temporarily, use the with statement.

wait_event(self, event)

Makes the stream wait for an event.

The future work on this stream will be done after the event.

Parameters

event (cupy.cuda.Event) – CUDA event.

__eq__(self, other)
__ne__(value, /)

Return self!=value.

__lt__(value, /)

Return self<value.

__le__(value, /)

Return self<=value.

__gt__(value, /)

Return self>value.

__ge__(value, /)

Return self>=value.

Attributes

done

True if all work on this stream has been done.

null = None