The timer values in the trace file exclude the time taken
to collect the trace data. Because an application can be idle (while
displaying a MessageBox, for example), percentage metrics are most
meaningful when you control tracing programmatically, which can
help minimize idle time. Percentages are less meaningful when you
create a trace file for a complete application.

Trace file names and labels

The default name of the trace file is the name of the application
with the extension PBP. The trace file is saved
in the directory where the PBL or executable
file resides and overwrites any existing file of the same name.
If you run several different tests on the same application, you
should change the trace file name for each test.

You can also associate a label with the trace data. If you
are tracing several different parts of an application in a single
test run, you can associate a different label with the trace data
(the trace block) for each part of the application.

Timer kinds

There are three kinds of timer: clock, process, and thread.
If your analysis does not require timing information, you can omit
timing information from the trace file to improve performance.

If you do not specify a timer kind, the time at which each
activity begins and ends is recorded using the clock timer, which
measures an absolute time with reference to an external activity,
such as the computer’s start-up time. The clock timer measures
time in microseconds. Depending on the speed of your computer’s
central processing unit, the clock timer can offer a resolution
of less than one microsecond. A timer’s resolution is the
smallest unit of time the timer can measure.

You can also use process or thread timers, which measure time
in microseconds with reference to when the process or thread being
executed started. You should always use the thread timer for distributed
applications. Both process and thread timers exclude the time taken
by any other running processes or threads so that they give you
a more accurate measurement of how long the process or thread is
taking to execute, but both have a lower resolution than the clock
timer.

Trace activities

You can choose to record in the trace file the time at which
any of the following activities occurs. If you are using the System
Options dialog box or a window, you select the check boxes for the
activities you want. If you are using PowerScript functions to collect
trace information, you use the TraceActivity enumerated
type to identify the activity.

When you begin and end tracing, an activity of type ActBegin!
is automatically recorded in the trace file. User-defined activities,
which you use to log informational messages to the trace file, are
the only trace activities enabled by default.