Point-To-Point Operations

Point-to-point operations enable direct communication between two specific entities, facilitating data exchange, synchronization, and coordination within a parallel computing environment.

The following point-to-point operations are available in oneCCL:

• send

• recv

send

send is a blocking point-to-point communication operation that transfers data from a designated memory buffer (buf) to a specific peer rank.

event CCL_API send(void *buf,
          size_t count,
          datatype dtype,
          int peer,
          const communicator &comm,
          const stream &stream,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event> &deps = {});

Parameters

• buf - A buffer with dtype count elements that contains the data to be sent.

• count - The number of dtype elements in a buf.

• dtype- The datatype of elements in a buf.

• peer - A destination rank.

• comm - A communicator for which the operation is performed.

• stream - A stream associated with the operation.

• attr - Optional attributes to customize the operation.

• deps - An optional vector of the events, on which the operation should depend.

Returns

ccl::event - An object to track the progress of the operation.

event CCL_API send(void* buf,
          size_t count,
          datatype dtype,
          int peer,
          const communicator &comm,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event> &deps = {});

Below you can find an overloaded member function provided for the convenience. It differs from the above function only in what argument(s) it accepts.

template <class BufferType,
    class = typename std::enable_if<is_native_type_supported<BufferType>(), event>::type>
event CCL_API send(BufferType *buf,
          size_t count,
          int peer,
          const communicator &comm,
          const stream &stream,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event>& deps = {});

Below you can find an overloaded member function provided for the convenience. It differs from the above function only in what argument(s) it accepts.:

event CCL_API send(BufferType *buf,
          size_t count,
          int peer,
          const communicator &comm,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event> &deps = {});

Below you can find an overloaded member function provided for the convenience. It differs from the above function only in what argument(s) it accepts.

event CCL_API send(BufferObjectType &buf,
          size_t count,
          int peer,
          const communicator &comm,
          const stream &stream,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event> &deps = {});

Below you can find an overloaded member function provided for the convenience. It differs from the above function only in what argument(s) it accepts.

event CCL_API send(BufferObjectType &buf,
          size_t count,
          int peer,
          const communicator &comm,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event> &deps = {});

recv

recv is a blocking point-to-point communication operation that receives data from a peer rank in a memory buffer.

event CCL_API recv(void *buf,
          size_t count,
          datatype dtype,
          int peer,
          const communicator &comm,
          const stream &stream,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event> &deps = {});

Parameters

• buf - A buffer with dtype count elements that contains where the data is received.

• count - The number of dtype elements in a buf.

• dtype- The datatype of elements in a buf.

• peer - A source rank.

• comm - A communicator for which the operation is performed.

• dtream - A stream associated with the operation.

• attr - Optional attributes to customize the operation.

• deps - An optional vector of the events, on which the operation should depend.

Returns:

ccl::event - An object to track the progress of the operation.

event CCL_API recv(void *buf,
          size_t count,
          datatype dtype,
          int peer,
          const communicator &comm,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event>& deps = {});

Below you can find an overloaded member function provided for the convenience. It differs from the above function only in what argument(s) it accepts.

template <class BufferType,
    class = typename std::enable_if<is_native_type_supported<BufferType>(), event>::type>
event CCL_API recv(BufferType *buf,
          size_t count,
          int peer,
          const communicator &comm,
          const stream &stream,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event> &deps = {});

Below you can find an overloaded member function provided for the convenience. It differs from the above function only in what argument(s) it accepts.

event CCL_API recv(BufferType *buf,
          size_t count,
          int peer,
          const communicator &comm,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event> &deps = {});

Below you can find an overloaded member function provided for the convenience. It differs from the above function only in what argument(s) it accepts.

event CCL_API recv(BufferObjectType &buf,
          size_t count,
          int peer,
          const communicator &comm,
          const stream &stream,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event> &deps = {});

Below you can find an overloaded member function provided for the convenience. It differs from the above function only in what argument(s) it accepts.

event CCL_API recv(BufferObjectType &buf,
          size_t count,
          int peer,
          const communicator &comm,
          const pt2pt_attr &attr = default_pt2pt_attr,
          const vector_class<event> &deps = {});