Dynamic Ramp Adjustment (Virtual User Ramp Controller)

Document created by Chris Sommerstad Employee on Jul 21, 2017Last modified by Trishala Kalal on Aug 14, 2017
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Virtual User Ramp Controller

Each CloudTest test composition has a ramp plan that consists of the Distributions of its Tracks and their ramp settings. A ramp plan has a goal, which is a total sum of Virtual Users (VUs) that is reached at mid-point for a given ramp. The Virtual User Ramp Controller widget provides the means to manually control and adjust the ramp (or current goal) during runtime. Using Dynamic Ramp Adjustment techniques, the current goal for a playing composition can be remixed to arrive at a new goal while composition plays. Runtime changes to the current goal don't take effect until the new goal is applied.

A ramp plan that exists at composition runtime is the current goal or planned ramp and continues to be in effect until some other plan is applied. In the shot above, the planned ramp (green line) of 100 VUs was nearly reached when the tester determined to take manual control and increase the VUs. This is the point in the graph where the blue and green lines separate.

Defining a new goal, which is to say, dynamically adjusting the current goal on-the-fly using a manual remix technique, is the job of the new Virtual User Ramp Controller widget.

TIP:  A Composition can also be started in Manual Mode by checking Start Composition in Manual Ramp Mode in the Composition properties, Play Settings tab (shown below). When a composition starts in Manual Ramp Mode, all of its Distributions start out at zero users and remain at zero until the controller is used to change something.

Since in many load test scenarios the test doesn't go "according to plan" (or the tester has no clear idea how the test will perform) this new ability to manually take control of a ramp during runtime is a huge leap forward. In prior releases, the user would need to use the Pause Ramp feature, tweak ramp settings, re-save, and then proceed accordingly. Using manual dynamic ramp adjustment, the user can take full control of the existing "ramp plan" for a load test while the composition plays.

By presenting both the current goal of the composition's ramp plan (top left) during runtime, and its new goal (top right), if any, the Virtual User Ramp Controller visually depicts the control of large load- and performance-tests in the cloud (as well as the potential impact of applied and not-yet-applied changes to the ramp plan during runtime).

The Controller has the following features:

  • A line chart (upper left) that displays the actual users and goals  

Note:  Add the controller to a dashboard in the Composition Editor, Play tab before beginning play. Use the Maximize icon on the controller toolbar to maximize into the full browser window.

Before play, the controller visually represents the current ramp settings, if executed (e.g., 100 VUs will be reached around 1:45 seconds, etc.).

The green line represents the planned ramp as it executes and is flat above since the composition is not yet playing. Once play ensues, the timeline starts and the ramp begins. The blue and green lines will be closely correlated in most cases. The ramp will morph along the timeline as VUs come up.

Once the VUs are reached, the ramp will plateau and if no changes are applied, the ramp down will begin at the specified time—all according to the current goal of the ramp plan.

  • A line chart (upper right) that is null before play begins.


  • Once play begins, the chart shows the current goal (time/VUs) of the planned ramp on its current arc.


The user can drag the goal's "handle" or type a new ramp goal to represent a possible change in the ramp's current goal.

  • A middle fader section that has a Master fader (middle right), and an additional mixer for each Distribution of each Track that has parallel repeat renewal set (all faders are text–enabled and accept user–entered values).

When the controller is first opened, the Master track is selected (blue highlighted).

Use the Master fader to control VUs for the entire composition or use the Distribution's fader to increase or decrease its level.

Select at the track level (i.e. Track 2) to enter changes for all its distributions (shown below).

Or, click into a given distribution within a track to edit only its VUs.

Alternately, enter the VUs into the text fader's entry field.

TIP:  Only Distributions of Tracks that use parallel repeat renewal have a per Track control.

  • A Hold button for each fader; placing a Track on hold puts each of its Distributions on hold. Hold only applies to each Distribution and doesn't cross Distributions. Toggle the Hold button to the "On" position to enforce that value for the given Distribution, or use the Master control to alter the ramp plan for the composition at-large.

  • A Reset Ramp Changes button that will undo non-applied changes and restore the prior state of the Controller.
  • An Apply Ramp Changes button that will apply and begin to execute ramp plan changes


  • A Mode indicator (bottom right) that displays whether the composition is under "Automatic" (e.g. using the current goal) or "Manual" control.


Note:  Since the widget communicates directly with the underlying Load Server(s), any applied changes are pushed to a given server so as to dynamically control the ramp (once Apply Ramp Changes is clicked).

  • A Legend that indicates the current goal for VUs as a blue line and the current "ideal ramp" as a green line. The scale shown is based on the actual ramp's scale.

  • A Ramp Notifications section that displays the underlying Load Servers activity after apply.


Once again, actual changes don't occur until they are applied. Once applied, pending updates are shown and the test proceeds under manual control.

Click the Plus (+) icon to expand the section and show more detail.

Remixing the Ramp Plan

The user can remix the ramp plan either by using a per-Distribution fader or the master-fader.

    Changes to the master affect all of the Distributions of Tracks shown.
  • Adjust faders in the controller to automatically preview their potential impact. The new "goal" is presented to the user in the upper right as well as in the Master fader.

For more about Ramp Settings, refer to Defining Ramps for a Track or Timed Clip.

In order to take manual control of a test composition, the Virtual User Ramp Controller widget must first be added to a dashboard. As with any settings, the ramp plan settings that exist at runtime are automatically executed during composition play.

To begin in the dashboard, add the Virtual User Ramp Controller.

  1. Right-click the composition's latest result in the Central > Compositions list.

< img src="http://cdn.soasta.com/findouthow/testassembly/img/cat4_topic15_img-20_popout.png" border="0" alt="Virtual User Ramp Controller" />

  1. If necessary, create a new dashboard for the Virtual User Ramp Controller. SOASTA recommends that the dashboard layout be "Fit Width and Scroll" with 1 column and one row (lowest right Widget Layout selection). Finish dashboard creation after making layout selection.

  1. In the dashboard, click the Toggle Widget Selection Panel icon to on.
  2. Expand the Widget Selection Panel, Widget Type, Basic section and then drag and drop the Virtual User Ramp Controller into place.

The Virtual User Ramp Controller widget appears in the dashboard.

  • Perform the desired ramp modifications by using Master or by individually controlling a Track (and its Distributions) or a Distribution (within a given Track), using any of the following methods:
  • To manually control Time and VUs drag the goal's "handle" to the VU level and to the desired time on the timeline.

Note that whatever the method of control, the upper right section depicts the impact of this change before apply. Ramp Mode in the lower right is still set to Automatic before apply is clicked.

  • To manually control all the Tracks/Distributions as one, you can also adjust the Master fader accordingly.
  • To manually control one or more Tracks/Distributions, enable each fader and adjust it accordingly. As with the Master fader, setting a Track's fader will also be depicted in the upper right before apply.
  1. Click Apply Ramp Changes to exit Automatic mode and enter Manual mode. Once this is done, the composition is explicitly under the user's control. Click Reset Ramp Changes to abandon the changes and remain in Automatic mode without changes to the composition's ramp settings.