Engines View

The Engines View provides configuration options for each engine that will be used during a load test. In order to connect to a load engine, you will need a test computer with the load engine software installed. For more information, please consult the Load Engines section.

For active engines ready to or actively participating in a load test, the following information is displayed:

Name
The name of the computer that the engines is running on. If the value is local, this indicates the load engine embedded in the controller (running on the current computer) is being used. This is not recommended if remote load engines are also being used.
Status
Indicates the state of the load engine. Possible values are "Offline", "Idle", "Running", "Initializing", and "Stopping."
Color
The color used to represent this engine in the graphs on the right side of the view.
Active Users
The number of virtual users actually running.
Estimated Users
The total number of virtual users that it appears the machine could generate. Note that the estimated number usually is inaccurate at lower load averages, so that your computer very well may be able to generate a larger number of virtual users. This is because at low load averages the estimation is not as accurate as at a high load average. Also, the response of many computers is nonlinear, so that the load average could hover at 20%, for example, and stay there while the number of virtual users climbs.
% CPU
The CPU utilization of the engine's computer, where 100% has all of the machine cycles being used. Note that on UNIX this value is greatly affected by background processes that are blocked, so even though a process isn't taking up any CPU time, if it is stuck in a disk wait or otherwise hung your load average will be higher. Use "ps", "top" or other programs to find and stop background processes that may be increasing the system load so that the full power of the computer is available for the performance test. Note that there is lag in getting the information from the operating system, so the value will not be exactly the same as the value displayed by other utilities.
% Memory
This measures how much of the memory allocated for internal buffers is actually in use. This number has no relation to any operating system specific information you might view using an OS utility such as Windows Task Manager. This value will go up and down during the performance test and could occasionally reach the low or out of memory values. It will slowly creep up towards the 80% mark when using large numbers of virtual users or when running the performance test for a long period of time. When the program absolutely has run out of memory you will see this value quickly climb into the 90% range every 30 seconds or so. When this happens, no more users will be added to the engine to prevent the program from running out of all memory and causing corrupt test results.
Version
The current version of the Load Engine software running on the engine.

Adding Engines

Many times, load engines are automatically detected and displayed in this view when the application is started, or when the load engine software is started. However, in some circumstances the engine may not be added automatically, and you will want to explicitly connect to an engine. Alternatively, you may want the local engine to also participate in the load test, in addition to it's role of collecting metrics and distributing users. For either of these options you may select the Add Engine button.

In the Add Engine dialog, you may select to add the local engine (only if it is not already selected as an engine), or select a remote engine. For remote engines, you may enter either the host name or the IP address for the engine. The port number used for engine communication defaults to 1099, and should only be changed if the remote engine has been explicitly configured to use another port. Once the OK button is pressed, Load Tester will attempt to connect to the engine, and verify that the engine is suitable for testing before adding it.

If you receive an error attempting to add an engine that is known to be running, then it may be necessary to configure any firewalls and the engine to permit connections with the controller. For more information, please see Configuring a Load Engine.

Selecting Engines

To select an engine to use during a load test (or to monitor live), select the checkbox next to the engine name. To disable an engine - un-check. Only those engines which are checked will be used during a load test. When selected, Load tester will attempt to verify that the engine is available for testing, and enable it if so.

Engines may also be removed entirely from the engine list by pressing the Remove button. Once an engine has been removed, it may be added back automatically if it or the controller is restarted.

Upgrading Engines

If the engine is using a different software version, it cannot be enabled. If the software version of the engine is lower, selecting the engine will enable the Upgrade button. Press it to upgrade the software on the engine. Once the upgrade process has completed, the remote engine software will need to be restarted in order for the upgrade to take affect.

Configuring Engines

For engines which support using multiple IP addresses, it is possible to configure which IP addresses the engine will use during a load test. To do this, select an enabled engine, and press the Configure IPs button. A dialog will be displayed allowing you to configure the IP Aliasing settings for the engine.

Viewing Historical Metrics

After a test has completed, selecting the test results will display the saved engine metrics from the selected test. Only the relevant columns will be displayed for historical data - which means none of the columns which show "live" data will be displayed.

Note that the live data option must be de-selected to view historical results: