The VU Activity Chart for a page or a transaction shows on the test timeline, which VUs requested the page or executed the transaction on different test iteration. It also shows on which agent it was emulated.

The VU Activity Chart helps to isolate performance issues by showing how load patterns and VUs concurrences correlate with slow pages/transactions. You can further drill down every page/transaction to display its waterfall, which breaks it down to the level of individual requests.

An example of a transaction VU Activity chart is provided on the right: 

  • Vertical axle shows VUs (a).
  • VUs 1-250 were emulated on a controller (b); VUs 251-500 were emulated on the agent (c).
  • Horizontal axle (d) is the timeline. The test duration was a little longer than one hour.
  • To zoom-in to a specific VUs/Iterations range, select an appropriate rectangular area (e).
  • Each page or transaction associated with a VU is depicted by a sequence of horizontal bars colored to highlight the alternate iterations: iterations, 1,3,5... are dark green (f); 2.4.6... are light green (g).
  • The length indicates how long it took to complete the page or transaction on this iteration.
  • To display details of each page /transaction, mouse over its bar (h).  The tooltip (i) will display the following information:
    • VU number
    • Iteration number
    • Iteration start and end time
    • Page/transaction duration
    • Page/transaction duration w/o think time
    • Agent name
    • Test case name

 Generating Test Iteration Waterfall

  • To display a waterfall of a page/transaction, Dbl-Click its horizontal bar, or right-click (j) and select View Waterfall.
  • You can compare the waterfalls of two iterations. To do so, after selecting the first waterfall, navigate back to VU Activity view and Ctrl+Dbl-Click the second iteration bar, or right-click it and select Compare Waterfalls.

Other Commands:

  • To zoom-out, right-click (k), and select Un-Zoom.
  • For additional context menu commands, right-click and select Copy Image, Save Image or Print Graph Image.

Export iteration data

  • You can export iteration data for every Page/Transaction. 
  • To export the data points right-click > select Export to CSV... (g)
  • The following data is exported:
    • VU number
    • Iteration number
    • Test case name
    • Page/Transaction name
    • Start: the number of ms from the start of the test the iteration started
    • End: the number of ms from the start of the test the iteration ended
    • Duration: the number of seconds End - Start
    • Duration w/o think time: number of seconds End - Start - think time
    • Agent name

Iteration summary:

When zooming the activity view, the bottom area will show iteration summary information for the zoomed range.

  • Start: the start time of the zoomed range
  • End: the end time of the zoomed range
  • Full transactions: the number of completed transactions in the zoomed range
  • Transactions/sec: the number of completed transactions per second in the zoomed range
  • Avg. transaction time: the average transaction time (including think time) of the completed iterations in the zoomed range.
  • Partial transactions: the number of transactions that started before the zoomed range and/or ended after the zoomed range.


Note: If the test stopped before a transaction completed, this transaction will count as a Full transaction if it falls into the entire zoomed range.

Filter by agent

If a load test run used more than one load agent, then the activity diagram can be filtered to show transaction activity per load agent.

To display the Activity Chart for one load agent, select it from the drop-down in the toolbar. By default, All is selected and displays activity for all load agents.


When filtering by agent, the iteration summary will also be filtered to show calculations only for the selected load agent. Also, the export feature will only export the data for the selected.

  • No labels