Pathway/iTS System Management Manual (G06.24+)

Tuning Your System Using Statistics
HP NonStop Pathway/iTS System Management Manual—426748-002
5-10
POOL INFO
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In general, TERMBUF should be large enough to hold the largest display sent
to a terminal. Although this might oversize TERMPOOL, the excess space is
held only for a short time, so system performance is not adversely affected.
The excess space is not used because, generally, the terminal is in a read
state rather than a write state.
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Defining too small a value for TERMBUF might increase the number of output
operations necessary to perform certain functions (for example, execution of
the SCREEN COBOL DISPLAY BASE statement).
•
Defining too large a value for TERMBUF might decrease the number of
terminals able to operate simultaneously or increase the number of times an
I/O operation is delayed until space for a buffer becomes available.
To adjust the size of TERMPOOL, use the STATS TCP display information (MAX
ALLOC) to determine the appropriate size. You can use this formula:
TERMPOOL = MAXTERMS * (MAX REQ + 2)
SERVERPOOL
SERVERPOOL, specified with the SET TCP SERVERPOOL command, indicates the
number of bytes that the TCP allocates for requests and replies between SCREEN
COBOL programs and server processes.
If SERVERPOOL space is insufficient, transactions must wait for the completion of
previous transactions before proceeding.
To determine sufficient size for SERVERPOOL, you need to estimate the number of
buffers required for the active transactions. (Every active transaction requires one
buffer.)
You can use these formulas to estimate a sufficient size for SERVERPOOL. This
formula gives you an upper limit for the size of SERVERPOOL:
SERVERPOOL=MAXREPLY*MAXSERVERS
This formula gives you a less memory-intensive estimate:
SERVERPOOL=MAXREPLY*MAX-TPS*EST-RESP-TIME*SAFETY-FACTOR
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MAXREPLY
specified with the SET TCP MAXREPLY command, indicates the maximum
number of bytes permitted for a SEND message or a REPLY message. This value
should be supplied by your application development group. To determine the
current value for MAXREPLY, use the INFO TCP command.
•
MAXSERVERS
defined with the SET SERVER MAXSERVERS command, is the maximum number
of server processes that can run in a server class at the same time. To determine
the current value of MAXSERVERS, use the INFO SERVER command. For
information about the SET SERVER MAXSERVERS and INFO SERVER
commands, see the TS/MP System Management Manual.