Response Time Graphs
The Response Time graphs illustrate the response time by the hour and by the day. All response
times are the system measured internal System i response times. They do not include the
transmission time on communications lines.
Response time is measured from points two through five, as shown in this figure.
The following numbered list describes the flow of a transaction in terms of response time
measurement.
1. The user presses Enter or a function key. This begins the response time period perceived by
the user. However, the system does not recognize the beginning of the transaction until Step
2.
Delays are typical on a communication line. They depend on:
The amount of current data traffic to and from other work stations on the line
How frequently the system polls the control unit for input data
2. This step indicates the Start of Transaction (SOT). In addition, the system performs the
following actions:
It identifies the beginning of the System Measured Response Time.
Workstation I/O Management (WSIOM) processes input from the display station. This
also represents the beginning of application-input queuing time.
3. This step indicates the Start of Resource Utilization Time (SOR). The application must issue
an input operation or accept an input operation. An application program receives the data
from WSIOM and begins using system resources to process the transaction. The application-
input queuing time ends at this point. Normally, application-input queuing time, like activity-
level waiting time, is only a few milliseconds.
74
PM for Power Systems Graph Reference Document
