HOST COMMAND SET REFERENCE
UNILINK HOST
ADAPTER 5–38
USER MANUAL
5.4.10
Allocate HIU Bandwidth — 19
The
ALLOCA
TE HIU
BANDWIDTH command allows an adapter configured as
an HIU to control how the NM buffers allocated for its use will be used. The
Network Manager allocates a fixed number of NM buffers for the HIU’s use,
which is the HIU’s bandwidth. This bandwidth processes direct commands,
non-repetitive macros, and repetitive macros. Since repetitive macros are
always ready for transmission, they will tend to use the entire bandwidth,
slowing
down the response for direct commands and non-repetitive macros.
The
first
parameter for this command
specifies a limit on the number of NM buffers
that
can be used for repetitive macros.
The
second parameter is to limit the number of outstanding requests for a single
secondary device. This prevents a single secondary device from getting the
entire bandwidth, thus leaving no room for requests for other secondaries. It
also prevents one HIU from dominating a secondary device and increasing its
access
delay for other HIUs.
This command may issued at any time after the HIU has been initialized and
the bandwidth allocated by the Network Manager. This helps tailor the
bandwidth
to changing network conditions.
Command:
19 ll nn
Response: 19
Usage: PERFORMANCE
Modes:
MHIU, HIU
Parameters:
ll The
maximum number of repetitive macros that can be
executing
at one time. Values range from 0 to the number of NM buffers
allocated
by
the Network Manager and will default to the number
of
NM buffers allocated by the Network Manager
.
nn The
number of outstanding requests per secondary
. V
alues
range
from one to the number of NM buffers allocated by the Network
Manager and will default to two requests per secondary or the
number of NM buffers allocated by the Network Manager,
whichever
is smaller
.