NAME

       fi_rxm - The RxM (RDM over MSG) Utility Provider

OVERVIEW

       The  RxM  provider (ofi_rxm) is an utility provider that supports RDM endpoint emulated over MSG endpoint
       of a core provider.

REQUIREMENTS

       RxM provider requires the core provider to support the following features:

       • MSG endpoints (FI_EP_MSG)

       • RMA read/write (FI_RMA)

       • FI_OPT_CM_DATA_SIZE of at least 24 bytes

SUPPORTED FEATURES

       The RxM provider currently supports FI_MSG, FI_TAGGED and FI_RMA capabilities.

       Endpoint types : The provider supports only FI_EP_RDM.

       Endpoint capabilities : The following data transfer interface is supported: FI_MSG, FI_TAGGED, FI_RMA.

       Progress : The RxM provider supports FI_PROGRESS_AUTO.

       Addressing Formats : FI_SOCKADDR, FI_SOCKADDR_IN

       Memory Region : FI_MR_VIRT_ADDR, FI_MR_ALLOCATED, FI_MR_PROV_KEY MR mode bits would be required from  the
       app in case the core provider requires it.

LIMITATIONS

       When  using  RxM  provider, some limitations from the underlying MSG provider could also show up.  Please
       refer to the corresponding MSG provider man pages to find about those limitations.

   Unsupported features
       RxM provider does not support the following features:

       • op_flags: FI_FENCE.

       • FI_ATOMIC

       • Scalable endpoints

       • Shared contexts

       • FABRIC_DIRECT

       • FI_MR_SCALABLE

       • Authorization keys

       • Application error data buffers

       • Multicast

       • FI_ADDR_STR, FI_SYNC_ERR

       • Reporting unknown source addr data as part of completions

       • Triggered operations

   Auto progress
       When sending large messages, an app doing an sread or waiting on the CQ file descriptor  may  not  get  a
       completion  when  reading  the CQ after being woken up from the wait.  The app has to do sread or wait on
       the file descriptor again.

RUNTIME PARAMETERS

       The ofi_rxm provider checks for the following environment variables.

       FI_OFI_RXM_BUFFER_SIZE : Defines the transmit buffer size / inject size.  Messages of size less than this
       would  be  transmitted  via  an  eager  protocol  and  those  above would be transmitted via a rendezvous
       protocol.  Transmit data would be copied up to this size (default: ~16k).

       FI_OFI_RXM_COMP_PER_PROGRESS : Defines the maximum number of MSG provider CQ entries  (default:  1)  that
       would be read per progress (RxM CQ read).

SEE ALSO

       fabric(7), fi_provider(7), fi_getinfo(3)

AUTHORS

       OpenFabrics.