Tandem Capacity Model (TCM) Manual

Fixed (system overhead that does not vary with throughput)F
Ignore these categories (appropriate interrupt and disk activity to be omitted)Z
5. Tunable CPU—Directly Modifiable
Tunable CPU applies to batch transactions only. Y indicates batch transactions are spread
evenly across all available batch CPUs. N indicates batch transactions are assigned to run in
only one CPU. For more information, see “CPU Tunability” (page 102).
6. Fixed CPU Sec Actual/Plan—Directly Modifiable
The Fixed CPU Sec Actual/Plan column is visible only when you select the Display Scratch
Areas option. The total number of CPU seconds consumed per second by process categories
of type F (fixed) is not included in the CPU and disk consumption of individual transactions,
but it does affect the total CPU and disk utilizations. Define a category as type F if its CPU
and disk consumption do not increase as throughput increases, such as during asynchronous
data communications polling activity or the running of Measure.
7. Priority—Directly Modifiable
Priority is the priority of the process category.
8. CPU Seconds—Not Directly Modifiable
CPU Seconds is the CPU seconds allocated to each transaction by process category.
9. Not shown. CPU Sec and DP CPU Sec Tables—Directly Modifiable
The CPU Sec and DP CPU Sec tables are visible only when you select the Display Scratch
Areas option. The values in these tables are the CPU seconds and DP CPU seconds allocated
to each transaction by the process category. Total CPU seconds per transaction is the sum of
the corresponding values in these two tables.
You can modify these values by overwriting the cells. For example, TCM Plan transaction costs
contain "Smart Cell Updating." If you change a formula to a value, TCM changes the entry
formula that yields the desired value, but will scale as necessary, depending on Plan CPU
type.
Capacity History Screens
The Capacity History screens–Database, TrendCharts, and MixCharts–are used to archive, organize,
and visualize apportioned performance data for a particular application or set of applications.
The information in the Capacity History database helps the capacity planner in such crucial activities
as:
• Checking the reasonableness of an apportionment method for a custom WA model
• Choosing a representative performance sample as a baseline for the TCM Performance model
• Projecting trends based on historical data in the Performance model
• Performing database queries against historical data
• Creating historical charts
The Capacity History screens display summary performance information for each transaction in a
given application (or set of applications) across multiple performance samples. The database can
also store data for several different apportionment methods, so the capacity planner can easily
examine the effect of different apportionment methods on several historical samples.
Capacity History Database Screen
Capacity planners can search the database by selecting Search from the History tab. Figure 52
(page 158) shows part of a sample Capacity History database screen.
Capacity History Screens 157