International Business Machines Corporation

Philip W Frey

Bernard Metzler

Fredy Daniel Neeser

Animesh Kumar Trivedi

A computer-implemented method, system, and article of manufacture for data communication between a requester and a responder in a remote direct memory access (RDMA) network, where each of the requester and the responder is an RDMA-enabled host of the network. The method includes: sending a request for the responder to provide data, where the request includes a mapped steering tag that is obtained by mapping a set of memory buffers of the requester onto a single representation that allows for identifying each of the memory buffers of the set; and receiving the requested data together with the mapped steering tag and assigning the data being received to the memory buffers of the set consistently with the mapping.

RDMA read destination buffers mapped onto a single representation

Exemplary embodiments include RDMA methods and systems for sending application data to a computer memory destination in a direct but non-blocking fashion. The method can include posting a new work request for an RDMA connection or association, determining if there is a prior work request for the same connection or association enqueued for processing, in response to a determination that no prior work request is enqueued for processing, processing the new work request directly by sending RDMA frames containing application data referred to by the work request to the computer memory destination, performing direct sending while there is sufficient send space to process the new work request, and delegating the new work request to asynchronous transmission if a prior work request is already enqueued for processing or lack of send space would block a subsequent transmission operation.

Direct sending and asynchronous transmission for RDMA software implementations

A method for data transmission on a device without intermediate buffering is provided. An application request is received to transmit data from the device to a second device over a network. The data from application memory is formatted for transmitting to the second device. The data are transmitted from the device to the second device without intermediate buffering. A send state is retrieved. The send state is compared to expected send state. If the send state meets the expected send state, a completion of the data transmit request is generated.

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Rueschlikon, Switzerland

Philip W Frey