NAME

       fi_rstream - The Rstream Fabric Provider

OVERVIEW

       The  rstream provider supports stream messaging over message based RMA.  It maps stream to
       message over a core RMA-based OFI  provider.   Only  Endpoints  and  EQs  are  needed  for
       connection  start-up  and messaging.  Unlike other OFI providers, rstream does not support
       CQs or memory registration of any kind.  In order to asynchronously wait for a  completion
       (cm/msg),  one  can  use fi_control on the endpoint/eq to get an fd to use in a poll call.
       For messaging completions, use FI_PEEK on  send/recv  after  poll  to  see  what  type  of
       transaction has transpired.

SUPPORTED FEATURES

       The rstream provider currently supports FI_MSG capabilities.

       Endpoint types
              The provider supports only endpoint type FI_EP_SOCK_STREAM.

       Endpoint capabilities : The following data transfer interface is supported: fi_msg.

       Modes  The  provider does not require the use of any mode bits but supports core providers
              that require FI_CONTEXT and FI_RX_CQ_DATA.

       Progress
              The rstream provider only supports FI_PROGRESS_MANUAL.

       Threading Model
              The provider supports FI_THREAD_SAFE

       Verbs-iWarp
              The provider has added features to enable iWarp.   To  use  this  feature,  the  ep
              protocol iWarp must be requested in an fi_getinfo call.

LIMITATIONS

       The  rstream  provider  is  experimental  and  lacks  performance validation and extensive
       testing.  The iWarp protocol may need extra initialization work to  re-enable.   Currently
       the  rstream  provider  is used to by the rsockets-OFI library as a ULP and hooks into the
       core provider verbs.  It is not interoperable with  the  previous  rsockets(v1)  protocol.
       There  are default settings that limit the message stream (provider memory region size and
       CQ size).  These can be modified by fi_setopt.

SETTINGS

       The  rstream  provider  settings  can  be  modified  via   fi_setopt   on   the   endpoint
       (FI_OPT_ENDPOINT) along with the following parameters:

       FI_OPT_SEND_BUF_SIZE
              Size of the send buffer.  Default is 32KB.

       FI_OPT_RECV_BUF_SIZE
              Size of the recv buffer.  Default is 32KB.

       FI_OPT_TX_SIZE
              Size of the send queue.  Default is 384.

       FI_OPT_RX_SIZE
              Size of the recv queue.  Default is 384.

OFI EXTENSIONS

       The  rstream  provider  has  extended  the  current  OFI API set in order to enable a user
       implementation of Poll.  Specifically sendmsg(FI_PEEK) is supported which  replicates  the
       behavior of the recvmsg(FI_PEEK) feature.

SEE ALSO

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

AUTHORS

       OpenFabrics.