Direct Access Transport Library Functions
dat_srq_post_recv(3DAT)
NAME
dat_srq_post_recv - add receive buffers to shared receive
queueSYNOPSIS
cc [ flag... ] file... -ldat [ library... ]
#include
DAT_RETURN
dat_srq_post_recv (
IN DAT_SRQ_HANDLE srq_handle,
IN DAT_COUNT num_segments,
IN DAT_LMR_TRIPLET *local_iov,
IN DAT_DTO_COOKIE user_cookie
)PARAMETERS
srq_handle A handle for an instance of the SRQ.
num_segments The number of lmr_triplets in local_iov. Can
be 0 for receiving a zero-size message.
local_iov An I/O Vector that specifies the local
buffer to be filled. Can be NULL forreceiving a zero-size message.
user_cookie A user-provided cookie that is returned to
the Consumer at the completion of the Receive DTO. Can be NULL.DESCRIPTION
The dat_srq_post_recv() function posts the receive buffer
that can be used for the incoming message into the local_iov
by any connected EP that uses SRQ.The num_segments argument specifies the number of segments
in the local_iov. The local_iov segments are filled in the
I/O Vector order until the whole message is received. This
ensures that all the front segments of the local_iov I/O
Vector are completely filled, only one segment is partially filled, if needed, and all segments that follow it are not filled at all. The actual order of segment fillings is left to the implementation.SunOS 5.11 Last change: 16 Jul 2004 1
Direct Access Transport Library Functionsdat_srq_post_recv(3DAT)
The user_cookie argument allows Consumers to have unique
identifiers for each DTO. These identifiers are completely under user control and are opaque to the Provider. There isno requirement on the Consumer that the value user_cookie
should be unique for each DTO. The user_cookie is returned
to the Consumer in the Completion event for the posted Receive.The completion of the posted Receive is reported to the Con-
sumer asynchronously through a DTO Completion event based on the configuration of the EP that dequeues the posted bufferand the specified completion_flags value for Solicited Wait
for the matching Send. If EP Recv Completion Flag isDAT_COMPLETION_UNSIGNALLED_FLAG, which is the default value
for SRQ EP, then all posted Recvs will generate completions with Signal Notifications.A Consumer should not modify the local_iov or its content
until the DTO is completed. When a Consumer does not adhereto this rule, the behavior of the Provider and the underly-
ing Transport is not defined. Providers that allow Consumersto get ownership of the local_iov but not the memory it
specified back after the dat_srq_post_recv() returns should
document this behavior and also specify its support in Pro-
vider attributes. This behavior allows Consumer full controlof the local_iov content after dat_srq_post_recv() returns.
Because this behavior is not guaranteed by all Providers,portable Consumers shall not rely on this behavior. Consu-
mers shall not rely on the Provider copying local_iov infor-
mation.The DAT_SUCCESS return of the dat_srq_post_recv() is at
least the equivalent of posting a Receive operation directlyby native Transport. Providers shall avoid resource alloca-
tion as part of dat_srq_post_recv() to ensure that this
operation is nonblocking. The completion of the Receive posted to the SRQ is equivalent to what happened to the Receive posted to the Endpoint for the Endpoint that dequeued the Receive buffer from the Shared Receive queue. The posted Recv DTO will complete with signal, equivalently to the completion of Recv posted directly to the Endpoint that dequeued the Recv buffer from SRQ withDAT_COMPLETION_UNSIGNALLED_FLAG value not set for it.
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Direct Access Transport Library Functionsdat_srq_post_recv(3DAT)
The posted Recv DTOs will complete in the order of Send postings to the other endpoint of each connection whoselocal EP uses SRQ. There is no ordering among different con-
nections regardless if they share SRQ and recv_evd or not.
If the reported status of the Completion DTO event corresponding to the posted RDMA Read DTO is notDAT_DTO_SUCCESS, the content of the local_iov is not defined
and the transfered_length in the DTO Completion event is not
defined. The operation is valid for all states of the Shared Receive Queue.The dat_srq_post_recv() function is asynchronous, nonblock-
ing, and its thread safety is Provider-dependent.
RETURN VALUES
DAT_SUCCESS The operation was successful.
DAT_INVALID_HANDLE The srq_handle argument is an
invalid DAT handle.DAT_INSUFFICIENT_RESOURCES The operation failed due to
resource limitations.DAT_INVALID_PARAMETER Invalid parameter. For exam-
ple, one of the IOV segments pointed to a memory outside its LMR.DAT_PROTECTION_VIOLATION Protection violation for local
or remote memory access. Protection Zone mismatch between an LMR of one of thelocal_iov segments and the
SRQ.DAT_PRIVILEGES_VIOLATION Privileges violation for local
or remote memory access. Oneof the LMRs used in local_iov
was either invalid or did notSunOS 5.11 Last change: 16 Jul 2004 3
Direct Access Transport Library Functionsdat_srq_post_recv(3DAT)
have the local write privileges.USAGE
For the best Recv operation performance, the Consumer shouldalign each buffer segment of local_iov to the Optimal Buffer
Alignment attribute of the Provider. For portable applica-
tions, the Consumer should align each buffer segment oflocal_iov to the DAT_OPTIMAL_ALIGNMENT.
Since any of the Endpoints that use the SRQ can dequeue the posted buffer from SRQ, Consumers should post a buffer large enough to handle incoming message on any of these Endpoint connections. The buffer posted to SRQ does not have a DTO completion flag value. Posting Recv buffer to SRQ is semantically equivalent to posting to EP withDAT_COMPLETION_UNSIGNALLED_FLAG is not set. The configura-
tion of the Recv Completion flag of an Endpoint that dequeues the posted buffer defines how DTO completion is generated. If the Endpoint Recv Completion flag isDAT_COMPLETION_SOLICITED_WAIT_FLAG then matching Send DTO
completion flag value for Solicited Wait determines if the completion will be Signalled or not. If the Endpoint RecvCompletion flag is not DAT_COMPLETION_SOLICITED_WAIT_FLAG,
the posted Recv completion will be generated with Signal. If the Endpoint Recv Completion flag isDAT_COMPLETION_EVD_THRESHOLD_FLAG, the posted Recv comple-
tion will be generated with Signal and dat_evd_wait thres-
hold value controls if the waiter will be unblocked or not. Only the Endpoint that is in Connected or Disconnect Pending states can dequeue buffers from SRQ. When an Endpoint is transitioned into Disconnected state, all the buffers thatit dequeued from SRQ are queued on the Endpoint recv_evd.
All the buffers that the Endpoint has not completed by the time of transition into Disconnected state and that have not completed message reception will be flushed.ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:SunOS 5.11 Last change: 16 Jul 2004 4
Direct Access Transport Library Functionsdat_srq_post_recv(3DAT)
______________________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Interface Stability | Committed ||_____________________________|_____________________________|
| MT-Level | Unsafe |
|_____________________________|_____________________________|
| Standard | uDAPL, 1.2 ||_____________________________|_____________________________|
SEE ALSO
dat_srq_create(3DAT), dat_srq_free(3DAT),
dat_srq_query(3DAT), dat_srq_resize(3DAT),
dat_srq_set_lw(3DAT), libdat(3LIB), attributes(5)
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Direct Access Transport Library Functionsdat_srq_post_recv(3DAT)
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