Manual Pages for UNIX Operating System command usage for man dat_lmr_sync_rdma_read

Direct Access Transport Library Functions
                                     dat_lmr_sync_rdma_read(3DAT)



NAME
     dat_lmr_sync_rdma_read - synchronize local memory with  RDMA
     read on non-coherent memory

SYNOPSIS
     cc [ flag... ] file... -ldat [ library... ]
     #include 

     DAT_RETURN
         dat_lmr_sync_rdma_read (
         IN DAT_IA_HANDLE ia_handle,
         IN const DAT_LMR_TRIPLET *local_segments,
         IN DAT_VLEN num_segments
         )


PARAMETERS
     ia_handle         A handle for an open instance of the IA.


     local_segments    An array of buffer segments.


     num_segments      The   number   of    segments    in    the
                       local_segments argument.


DESCRIPTION
     The dat_lmr_sync_rdma_read() function makes  memory  changes
     visible  to  an incoming RDMA Read operation. This operation
     guarantees consistency by locally flushing the  non-coherent
     cache  prior  to it being retrieved by remote peer RDMA read
     operations.


     The dat_lmr_sync_rdma_read() function is needed if and  only
     if  the  Provider attribute specifies that this operation is
     needed prior to an incoming RDMA Read operation. The  Consu-
     mer  must call dat_lmr_sync_rdma_read() after modifying data
     in a memory range in this region that will be the target  of
     an      incoming      RDMA      Read      operation.     The
     dat_lmr_sync_rdma_read() function must be called  after  the
     Consumer  has  modified the memory range but before the RDMA
     Read  operation  begins.  The  memory  range  that  will  be
     accessed  by the RDMA read operation must be supplied by the
     caller in the local_segments array. After this call returns,
     the RDMA Read operation can safely see the modified contents
     of the memory range. It is permissible to batch synchroniza-
     tions  for multiple RDMA Read operations in a single call by
     passing a local_segments array that  includes  all  modified
     memory  ranges.  The local_segments entries need not contain



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Direct Access Transport Library Functions
                                     dat_lmr_sync_rdma_read(3DAT)



     the same LMR and need not be in the same Protection Zone.


     If the Provider attribute specifying that this operation  is
     required  attempts  to  read from a memory range that is not
     properly synchronized  using  dat_lmr_sync_rdma_read(),  the
     returned contents are undefined.

RETURN VALUES
     DAT_SUCCESS              The operation was successful.


     DAT_INVALID_HANDLE       The DAT handle is invalid.


     DAT_INVALID_PARAMETER    One of the parameters  is  invalid.
                              For  example, the address range for
                              a local segment  fell  outside  the
                              boundaries   of  the  corresponding
                              Local Memory Region or the LMR han-
                              dle was invalid.


USAGE
     Determining when an RDMA Read will  start  and  what  memory
     range  it  will  read  is the Consumer's responsibility. One
     possibility is to have the Consumer that is modifying memory
     call  dat_lmr_sync_rdma_read() and then post a Send DTO mes-
     sage that identifies the range in the body of the Send.  The
     Consumer  wanting  to perform the RDMA Read can receive this
     message and know when it is safe to initiate the  RDMA  Read
     operation.


     This call ensures that the Provider receives a coherent view
     of  the  buffer  contents upon a subsequent remote RDMA Read
     operation. After the call completes,  the  Consumer  can  be
     assured  that all platform-specific buffer and cache updates
     have been performed, and that the LMR range has  consistency
     with the Provider hardware. Any subsequent write by the Con-
     sumer  can  void  this  consistency.  The  Provider  is  not
     required to detect such access.


     The action performed on  the  cache  before  the  RDMA  Read
     depends on the cache type:

         o    I/O noncoherent cache will be invalidated.

         o    CPU noncoherent cache will be flushed.




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Direct Access Transport Library Functions
                                     dat_lmr_sync_rdma_read(3DAT)



ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | Unsafe                      |
    |_____________________________|_____________________________|
    | Standard                    | uDAPL, 1.2                  |
    |_____________________________|_____________________________|


SEE ALSO
     dat_lmr_sync_rdma_write(3DAT), libdat(3LIB), attributes(5)



































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Direct Access Transport Library Functions
                                     dat_lmr_sync_rdma_read(3DAT)






















































SunOS 5.11          Last change: 16 Jul 2004                    4