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 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 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, due to the overhead of accessing the high resolution
timer on the Windows operating system. Typically, processor usage
increases by 10 to 25 percent, but the increase can vary based on
workload. Enable the high resolution timer on Windows agent computers
if you are measuring response times of 15 milliseconds or less, or
if you are measuring response times of 150 milliseconds or less 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 tradeoff of higher
processor usage is acceptable.
About this task
To enable the high resolution timer on an agent computer:
Procedure
- 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 new property for the selected location.
- In the New Property window, create
a new 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 now enabled for the location.