Tribblix: manual page: dat_ep_post

DAT_EP_POST_SEND(3DAT) Direct Access Transport Library Functions

NAME

dat_ep_post_send - transfer data to the remote side

SYNOPSIS

cc [ flag... ] file... -ldat [ library... ]
#include <dat/udat.h>

DAT_RETURN
dat_ep_post_send (
IN DAT_EP_HANDLE ep_handle,
IN DAT_COUNT num_segments,
IN DAT_LMR_TRIPLET *local_iov,
IN DAT_DTO_COOKIE user_cookie,
IN DAT_COMPLETION_FLAGS completion_flags
)

PARAMETERS

ep_handle
Handle for an instance of the Endpoint.

num_segments
Number of lmr_triplets in local_iov. Can be 0 for
0 size message.

local_iov
I/O Vector that specifies the local buffer that
contains data to be transferred. Can be NULL for
0 size message.

user_cookie:
User-provided cookie that is returned to the
Consumer at the completion of the send. Can be
NULL.

completion_flags
Flags for posted Send. The default
DAT_COMPLETION_DEFAULT_FLAG is 0x00. Other
values are as follows:

Completion Suppression
DAT_COMPLETION_SUPPRESS_FLAG

0x01
Suppress
successful
Completion.

Solicited Wait
DAT_COMPLETION_SOLICITED_WAIT_FLAG

0x02
Request for
notification
completion
for
matching
receive on
the other
side of the
connection.

Notification of Completion
DAT_COMPLETION_UNSIGNALLED_FLAG

0x04
Non-
notification
completion.
Local
Endpoint
must be
configured
for
Notification
Suppression.

Barrier Fence
DAT_COMPLETION_BARRIER_FENCE_FLAG

0x08
Request for
Barrier
Fence.

DESCRIPTION

The dat_ep_post_send() function requests a transfer of all the data
from the local_iov over the connection of the ep_handle Endpoint to
the remote side.

The num_segments parameter specifies the number of segments in the
local_iov. The local_iov segments are traversed in the I/O Vector
order until all the data is transferred.

A Consumer cannot modify the local_iov or its content until the DTO
is completed. When a Consumer does not adhere to this rule, the
behavior of the Provider and the underlying Transport is not defined.
Providers that allow Consumers to get ownership of the local_iov back
after the dat_ep_post_send() returns should document this behavior
and also specify its support in Provider attributes. This behavior
allows Consumers full control of the local_iov, but not the memory it
specifies after dat_ep_post_send() returns. Because this behavior is
not guaranteed by all Providers, portable Consumers should not rely
on this behavior. Consumers should not rely on the Provider copying
local_iov information.

The DAT_SUCCESS return of the dat_ep_post_send() is at least the
equivalent of posting a Send operation directly by native Transport.
Providers should avoid resource allocation as part of
dat_ep_post_send() to ensure that this operation is nonblocking and
thread safe for an UpCall.

The completion of the posted Send is reported to the Consumer
asynchronously through a DTO Completion event based on the specified
completion_flags value. The value of DAT_COMPLETION _UNSIGNALLED_FLAG
is only valid if the Endpoint Request Completion Flags
DAT_COMPLETION_UNSIGNALLED_FLAG. Otherwise, DAT_INVALID_PARAMETER is
returned.

The user_cookie allows Consumers to have unique identifiers for each
DTO. These identifiers are completely under user control and are
opaque to the Provider. There is no 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
Send.

The operation is valid for the Endpoint in the DAT_EP_STATE_CONNECTED
and DAT_EP_STATE_DISCONNECTED states. If the operation returns
successfully for the Endpoint in the DAT_EP_STATE_DISCONNECTED state,
the posted Send is immediately flushed to request_evd_handle.

RETURN VALUES

DAT_SUCCESS
The operation was successful.

DAT_INSUFFICIENT_RESOURCES
The operation failed due to resource
limitations.

DAT_INVALID_PARAMETER
Invalid parameter. For example, one of
the IOV segments pointed to a memory
outside its LMR.

DAT_INVALID_HANDLE
The ep_handle parameter is invalid.

DAT_INVALID_STATE
A parameter is in an invalid state.
Endpoint was not in the
DAT_EP_STATE_CONNECTED or
DAT_EP_STATE_DISCONNECTED state.

DAT_PROTECTION_VIOLATION
Protection violation for local or
remote memory access. Protection Zone
mismatch between an LMR of one of the
local_iov segments and the local
Endpoint.

DAT_PRIVILEGES_VIOLATION
Privileges violation for local or
remote memory access. One of the LMRs
used in local_iov was either invalid or
did not have the local read privileges.

USAGE

For best Send operation performance, the Consumer should align each
buffer segment of local_iov to the Optimal Buffer Alignment attribute
of the Provider. For portable applications, the Consumer should align
each buffer segment of local_iov to the DAT_OPTIMAL_ALIGNMENT.

ATTRIBUTES