Tandem Capacity Model (TCM) Manual

TMF processes (including all audit disk processes)T
Linehandler processL
OtherO
Fixed (system overhead that does not vary with throughput)F
Ignore these categories (appropriate interrupt and disk activity to be omitted)Z
3. Tunable CPU—Modifiable by the TCM administrator
This column indicates, for batch transactions only, whether all process category activity occurs
in one or multiple CPUs. It is ignored for online transactions. The process category CPU activity
is either monolithic or spread evenly across all CPUs that are available for batch activity. The
default is Y (yes) for categories that participate in at least one OLTP transaction. The default
is N (no) for categories that participate only in batch transactions.
For example, in the Demo model included with TCM, the Tape Read and Cust Update
categories are not tunable. That is, they are assigned to run in specific CPUs. However, the
FastSort category is tunable. It runs in all CPUs.
4. Expert Flag—Modifiable by the TCM administrator
This column shows whether TCM Expert generates a value for the process category. The default
for the TMF (T), Disk (D), Fixed (F), and Ignore (Z) process categories is N (no). The default is
also N for server categories whose names exactly match the transaction names because a
process category that has the same name as a server is assumed to have all activity for that
server. The default value for all other process categories is Y (yes).
5. Rcv and Sends—Modifiable by the TCM administrator
The Rcvs and Sends refer to the receives to or sends from process category, not the receives
to or sends from transaction. The entries in the table are multipliers of the process category
receives or sends. To compute the number of transactions, the entries listed in the two columns
below the transaction name are multiplied by the appropriate number of sends or receives of
the associated process category and the resultant products are added together. Therefore,
the zero entries provide no contribution. Negative numbers can be entered in the table.
For example, in the following table, the number of Txn1 transactions is equal to the number
of messages received by the Cat1 process category. (This is a common situation when Cat1
is the Pathway server class for Txn1.) In addition, the number of Txn2 transactions is equal to
half of the number of messages received by Cat2, minus the messages sent by Cat1.
Txn2Txn1
SendRcvSendRcv
-1001Cat1
0.500Cat2
0000Cat3
The Transaction Count table is used by the TCM administrator to indicate how to compute the
number of transactions from the number of messages received, sent or both by process
categories.
A default version of the table is automatically created when the user creates WA model.
Alternately, default version of the table can be created by selecting Workload Apportionment
from the Update menu and selecting Create Default Apportionment Tables from the dialog
box that appears. The table assumes that the transaction count for a specific transaction is
equal to the sum of the messages received by the server categories that participate in that
transaction. For more information see “Example of a Transaction Count Table” (page 72).
Transaction Count Table 119