DAT_SRQ_RESIZE(3DAT) Direct Access Transport Library Functions

NAME

dat_srq_resize - modify the size of the shared receive queue

SYNOPSIS

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

DAT_RETURN
dat_srq_resize (
IN DAT_SRQ_HANDLE srq_handle,
IN DAT_COUNT srq_max_recv_dto
)

PARAMETERS

srq_handle
A handle for an instance of the SRQ.


srq_max_recv_dto
The new maximum number of Recv DTOs that Shared
Receive Queue must hold.

DESCRIPTION

The dat_srq_resize() function modifies the size of the queue of SRQ.


Resizing of Shared Receive Queue should not cause any incoming
messages on any of the EPs that use the SRQ to be lost. If the number
of outstanding Recv buffers on the SRQ is larger then the requested
srq_max_recv_dto, the operation returns DAT_INVALID_STATE and do not
change SRQ. This includes not just the buffers on the SRQ but all
outstanding Receive buffers that had been posted to the SRQ and whose
completions have not reaped yet. Thus, the outstanding buffers
include the buffers on SRQ, the buffers posted to SRQ at are at SRQ
associated EPs, and the buffers posted to SRQ for which completions
have been generated but not yet reaped by Consumer from recv_evds of
the EPs that use the SRQ.


If the requested srq_max_recv_dto is below the SRQ low watermark, the
operation returns DAT_INVALID_STATE and does not change SRQ.

RETURN VALUES

DAT_SUCCESS
The operation was successful.


DAT_INVALID_HANDLE
The srq_handle argument is an invalid
DAT handle.


DAT_INVALID_PARAMETER
The srq_max_recv_dto argument is
invalid.


DAT_INSUFFICIENT_RESOURCES
The operation failed due to resource
limitations.


DAT_INVALID_STATE
Invalid state. Either the number of
entries on the SRQ exceeds the
requested SRQ queue length or the
requested SRQ queue length is smaller
than the SRQ low watermark.

USAGE

The dat_srq_resize() function is required not to lose any buffers.
Thus, it cannot shrink below the outstanding number of Recv buffers
on SRQ. There is no requirement to shrink the SRQ to return
DAT_SUCCESS.


The quality of the implementation determines how closely to the
Consumer-requested value the Provider shrinks the SRQ. For example,
the Provider can shrink the SRQ to the Consumer-requested value and
if the requested value is smaller than the outstanding buffers on
SRQ, return DAT_INVALID_STATE; or the Provider can shrink to some
value larger than that requested by the Consumer but below current
SRQ size; or the Provider does not change the SRQ size and still
returns DAT_SUCCESS.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+----------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+----------------------+
|Interface Stability | Standard: uDAPL, 1.2 |
+--------------------+----------------------+
|MT-Level | Unsafe |
+--------------------+----------------------+

SEE ALSO

dat_srq_create(3DAT), dat_srq_free(3DAT), dat_srq_post_recv(3DAT),
dat_srq_query(3DAT), dat_srq_set_lw(3DAT), libdat(3LIB),
attributes(7)

July 16, 2004 DAT_SRQ_RESIZE(3DAT)