You can configure agent computers to use a high-resolution
timer when collecting performance data. The high-resolution timer
ensures that all measurements are precise to within 1 millisecond.
Before you begin
The high-resolution timer is used by default on the Linux operating system. You do
not need to configure the high-resolution timer on the Linux operating system. For the Microsoft Windows, AIX®, and z/OS® operating systems, the high-resolution
timer is not used by default.
Enabling the high-resolution timer
can increase processor usage on Windows agent computers. Typically, processor usage increases
by 10% to 25%, but the increase can vary based on workload. Enable
the high-resolution timer on Windows agent computers if you are measuring response times less than 15
milliseconds. Enable the high-resolution timer if you are measuring
response times of less than 150 milliseconds and need 1 millisecond
precision instead of 15 millisecond precision. If you enable the high-resolution
timer on Windows agent computers,
monitor the processor usage to determine whether the trade-off of
higher processor usage is acceptable.
Procedure
To enable the high-resolution timer on an agent computer:
- In the Test Navigator, open the location that represents
the agent computer.
- Click the General Properties tab.
- On the General Properties page, click Add to create a property for the selected location.
- In the New Property window, create
a property entry:
- In Property Name, type RPT_VMARGS.
- In Operator, select =.
- In Property Value, type -DrptNanoTime.
If you need to set multiple RPT_VMARGS values for a location,
place them in the same property entry and separate them with a space.
Do not use multiple property entries to set multiple RPT_VMARGS values
for a location.
- Click OK, and then save the location. The high-resolution timer is enabled for the location.