dat_ep_create_with_DirectAAccess Transport Librarydat_ep_create_with_srq(3DAT)NAMEdat_ep_create_with_srq - create an instance of End Point with Shared
Receive Queue
SYNOPSIS
cc [ flag... ] file... -ldat [ library... ]
#include <dat/udat.h>
DAT_RETURN
dat_ep_create_with_srq (
IN DAT_IA_HANDLE ia_handle,
IN DAT_PZ_HANDLE pz_handle,
IN DAT_EVD_HANDLE recv_evd_handle,
IN DAT_EVD_HANDLE request_evd_handle,
IN DAT_EVD_HANDLE connect_evd_handle,
IN DAT_SRQ_HANDLE srq_handle,
IN DAT_EP_ATTR *ep_attributes,
OUT DAT_EP_HANDLE *ep_handle
)
PARAMETERS
ia_handle Handle for an open instance of the IA to which
the created Endpoint belongs.
pz_handle Handle for an instance of the Protection Zone.
recv_evd_handle Handle for the Event Dispatcher where events for
completions of incoming (receive) DTOs are
reported. DAT_HANDLE_NULL specifies that the Con‐
sumer is not interested in events for completions
of receives.
request_evd_handle Handle for the Event Dispatcher where events for
completions of outgoing (Send, RDMA Write, RDMA
Read, and RMR Bind) DTOs are reported. DAT_HAN‐
DLE_NULL specifies that the Consumer is not
interested in events for completions of requests.
connect_evd_handle Handle for the Event Dispatcher where Connection
events are reported. DAT_HANDLE_NULL specifies
that the Consumer is not interested in connection
events for now.
srq_handle Handle for an instance of the Shared Receive
Queue.
ep_attributes Pointer to a structure that contains Consumer-
requested Endpoint attributes. Cannot be NULL.
ep_handle Handle for the created instance of an Endpoint.
DESCRIPTION
The dat_ep_create_with_srq() function creates an instance of an End‐
point that is using SRQ for Recv buffers is provided to the Consumer as
ep_handle. The value of ep_handle is not defined if the DAT_RETURN is
not DAT_SUCCESS.
The Endpoint is created in the Unconnected state.
Protection Zone pz_handle allows Consumers to control what local memory
the Endpoint can access for DTOs except Recv and what memory remote
RDMA operations can access over the connection of a created Endpoint.
Only memory referred to by LMRs and RMRs that match the Endpoint Pro‐
tection Zone can be accessed by the Endpoint. The Recv DTO buffers PZ
must match the SRQ PZ. The SRQ PZ might or might not be the same as the
EP one. Check Provider attribute for the support of different PZs
between SRQ and its EPs.
The recv_evd_handle and request_evd_handle arguments are Event Dis‐
patcher instances where the Consumer collects completion notifications
of DTOs. Completions of Receive DTOs are reported in recv_evd_handle
Event Dispatcher, and completions of Send, RDMA Read, and RDMA Write
DTOs are reported in request_evd_handle Event Dispatcher. All comple‐
tion notifications of RMR bindings are reported to a Consumer in
request_evd_handle Event Dispatcher.
All Connection events for the connected Endpoint are reported to the
Consumer through connect_evd_handle Event Dispatcher.
Shared Receive Queue srq_handle specifies where the EP will dequeue
Recv DTO buffers.
The created EP can be reset. The relationship between SRQ and EP is not
effected by dat_ep_reset(3DAT).
SRQ can not be disassociated or replaced from created EP. The only way
to disassociate SRQ from EP is to destroy EP.
Receive buffers cannot be posted to the created Endpoint. Receive buf‐
fers must be posted to the SRQ to be used for the created Endpoint.
The ep_attributes parameter specifies the initial attributes of the
created Endpoint. Consumer can not specify NULL for ep_attributes but
can specify values only for the parameters needed and default for the
rest.
For max_request_dtos and max_request_iov, the created Endpoint will
have at least the Consumer requested values but might have larger val‐
ues. Consumer can query the created Endpoint to find out the actual
values for these attributes. Created Endpoint has the exact Consumer
requested values for max_recv_dtos, max_message_size, max_rdma_size,
max_ rdma_read_in, and max_rdma_read_out. For all other attributes,
except max_recv_iov that is ignored, the created Endpoint has the exact
values requested by Consumer. If Provider cannot satisfy the Consumer
requested attribute values the operation fails.
RETURN VALUES
DAT_SUCCESS The operation was successful.
DAT_INSUFFICIENT_RESOURCES The operation failed due to resource lim‐
itations.
DAT_INVALID_HANDLE Invalid DAT handle.
DAT_INVALID_PARAMETER Invalid parameter. One of the requested
EP parameters or attributes was invalid
or a combination of attributes or parame‐
ters is invalid. For example, pz_handle
specified does not match the one for SRQ
or the requested maximum RDMA Read IOV
exceeds IA capabilities..
DAT_MODEL_NOT_SUPPORTED The requested Provider Model was not sup‐
ported.
USAGE
The Consumer creates an Endpoint prior to the establishment of a con‐
nection. The created Endpoint is in DAT_EP_STATE_UNCONNECTED. Consumers
can do the following:
1. Request a connection on the Endpoint through dat_ep_con‐
nect(3DAT) or dat_ep_dup_connect(3DAT) for the active side
of the connection model.
2. Associate the Endpoint with the Pending Connection Request
that does not have an associated local Endpoint for accept‐
ing the Pending Connection Request for the passive/server
side of the con-nection model.
3. Create a Reserved Service Point with the Endpoint for the
passive/server side of the connection model. Upon arrival of
a Connection Request on the Service Point, the Consumer
accepts the Pending Connection Request that has the Endpoint
associated with it.
The Consumer cannot specify a request_evd_handle (recv_evd_handle) with
Request Completion Flags (Recv Completion Flags) that do not match the
other Endpoint Completion Flags for the DTO/RMR completion streams that
use the same EVD. If request_evd_handle (recv_evd_ handle) is used for
request (recv) completions of an Endpoint whose associated Request
(Recv) Completion Flag attribute is DAT_COMPLETION_UNSIGNALLED_FLAG,
the Request Completion Flags and Recv Completion Flags for all Endpoint
completion streams that use the EVD must specify the same. By defini‐
tion, completions of all Recv DTO posted to SRQ complete with Signal.
Analogously, if recv_evd_handle is used for recv completions of an End‐
point whose associated Recv Completion Flag attribute is DAT_COMPLE‐
TION_SOLICITED_WAIT, the Recv Completion Flags for all Endpoint Recv
completion streams that use the same EVD must specify the same Recv
Completion Flags attribute value and the EVD cannot be used for any
other event stream types. If recv_evd_handle is used for Recv comple‐
tions of an Endpoint that uses SRQ and whose Recv Completion Flag
attribute is DAT_COMPLETION_EVD_THRESHOLD then all Endpoint DTO comple‐
tion streams (request and/or recv completion streams) that use that
recv_evd_handle must specify DAT_COMPLETION_EVD_THRESHOLD. Other event
stream types can also use the same EVD.
Consumers might want to use DAT_COMPLETION_UNSIGNALLED_FLAG for Request
and/or Recv completions when they control locally with posted DTO/RMR
completion flag (not needed for Recv posted to SRQ) whether posted
DTO/RMR completes with Signal or not. Consumers might want to use
DAT_COMPLETION_SOLICITED_WAIT for Recv completions when the remote
sender side control whether posted Recv competes with Signal or not or
not. uDAPL Consumers might want to use DAT_COMPLETION_EVD_THRESHOLD for
Request and/or Recv completions when they control waiter unblocking
with the threshold parameter of the dat_evd_wait(3DAT).
Some Providers might restrict whether multiple EPs that share a SRQ can
have different Protection Zones. Check the srq_ep_pz_difference_support
Provider attribute for it.
Consumers might want to have a different PZ between EP and SRQ. This
allows incoming RDMA operations to be specific to this EP PZ and not
the same for all EPs that share SRQ. This is critical for servers that
supports multiple independent clients.
The Provider is strongly encouraged to create an EP that is ready to be
connected. Any effects of previous connections or connection establish‐
ment attempts on the underlying Transport-specific Endpoint to which
the DAT Endpoint is mapped to should be hidden from the Consumer. The
methods described below are examples:
o The Provider does not create an underlying Transport End‐
point until the Consumer is connecting the Endpoint or
accepting a connection request on it. This allows the
Provider to accumulate Consumer requests for attribute set‐
tings even for attributes that the underlying transport does
not allow to change after the Transport Endpoint is created.
o The Provider creates the underlying Transport Endpoint or
chooses one from a pool of Provider-controlled Transport
Endpoints when the Consumer creates the Endpoint. The
Provider chooses the Transport Endpoint that is free from
any underlying internal attributes that might prevent the
Endpoint from being connected. For IB and IP, that means
that the Endpoint is not in the TimeWait state. Changing of
some of the Endpoint attributes becomes hard and might
potentially require mapping the Endpoint to another underly‐
ing Transport Endpoint that might not be feasible for all
transports.
o The Provider allocates a Transport-specific Endpoint without
worrying about impact on it from previous connections or
connection establishment attempts. Hide the Transport-spe‐
cific TimeWait state or CM timeout of the underlying trans‐
port Endpoint within dat_ep_connect(3DAT), dat_ep_dup_con‐
nect(3DAT), or dat_cr_accept(3DAT). On the Active side of
the connection establishment, if the remnants of a previous
connection for Transport-specific Endpoint can be hidden
within the Timeout parameter, do so. If not, generating
DAT_CONNECTION_ EVENT_NON_PEER_REJECTED is an option. For
the Passive side, generating a DAT_CONNECTION_COMPLE‐
TION_ERROR event locally, while sending a non-peer-reject
message to the active side, is a way of handling it.
Any transitions of an Endpoint into an Unconnected state can be handled
similarly. One transition from a Disconnected to an Unconnected state
is a special case.
For dat_ep_reset(3DAT), the Provider can hide any remnants of the pre‐
vious connection or failed connection establishment in the operation
itself. Because the operation is synchronous, the Provider can block
in it until the TimeWait state effect of the previous connection or
connection setup is expired, or until the Connection Manager timeout of
an unsuccessful connection establishment attempt is expired. Alterna‐
tively, the Provider can create a new Endpoint for the Consumer that
uses the same handle.
DAT Providers are required not to change any Consumer-specified End‐
point attributes during connection establishment. If the Consumer does
not specify an attribute, the Provider can set it to its own default.
Some EP attributes, like outstanding RDMA Read incoming or outgoing, if
not set up by the Consumer, can be changed by Providers to establish
connection. It is recommended that the Provider pick the default for
outstanding RDMA Read attributes as 0 if the Consumer has not specified
them. This ensures that connection establishment does not fail due to
insufficient outstanding RDMA Read resources, which is a requirement
for the Provider.
The Provider is not required to check for a mismatch between the maxi‐
mum RDMA Read IOV and maximum RDMA Read outgoing attributes, but is
allowed to do so. In the later case it is allowed to return
DAT_INVALID_ PARAMETER when a mismatch is detected. Provider must allo‐
cate resources to satisfy the combination of these two EP attributes
for local RDMA Read DTOs.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │Safe │
├─────────────────────────────┼─────────────────────────────┤
│Standard │uDAPL, 1.2 │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOdat_ep_create(3DAT), dat_srq_create(3DAT), dat_srq_free(3DAT),
dat_srq_query(3DAT), libdat(3LIB), attributes(5)SunOS 5.11 16 Jul 2004 dat_ep_create_with_srq(3DAT)
