Summary Graphs


Summary Graphs contain a number of graphs that display the consolidated information on all user profiles of the current test scenario. You can view Summary Graphs on test completion to know how tests were performed. You can also view intermediate results at run-time while your test is being executed.

Click on the Summary Graphs item in the Navigation Pane to display the chart. There are several tabs on the chart:

Performance
Bandwidth
Errors
Server Performance
SQL Performance
Custom



You can manually choose what graphs will be shown on the chart. Check/uncheck options below the chart to show/hide graphs. You can check the All option to display all graphs on this tab.

X axis denotes the time interval of test run. Y axis is different for various graphs. For example:
: The number of active users is displayed on the right side of the chart.
: The number of pages executed per second is displayed on the left side of the chart.

If you place the mouse cursor over a graph node, the value in the current node will pop up.
If you cannot see the whole graph at once, you can drag it with the mouse to view all its parts.
You can increase/decrease the scale of any axis on the chart. Place the mouse cursor over axis values and drag them to get a desired scale.

Autofit chart
You can use the Autofit chart option to scale the graph down to window size. Double-clicking on the chart will have the same result.

Resample
If there are too many nodes displayed on the chart and neighbour nodes merge together, you can resample the graph with the Resample arrow.

Performance


Avg response time: Shows values of response time averaged through all user profiles. This is response time for main page requests (without page elements).

Average response time is one of the most important characteristics of load testing; it measures web user experience. Response time graph will tell you how long a user waits for server response to his request.

Below are 3 possible variants of Response time graph behavior when the number of users is increasing:

1. Flat (or very slight growth): It is an ideal result. The increase of load on the server doesn't lead to the increase of response time (or leads to very slight growth).
2. Gradual growth (essential growth): The increase of load on the server leads to gradual growth of response time. It means that the server can handle the growing level of load until the load exceeds some maximum value. Possible reasons of such situation are problems with server hardware, for example, insufficient network bandwidth or low productivity of the server.
3. Sharp growth: If response time graph exhibits a sharp growth beginning from some level of user load while download time graph doesn't grow essentially, it means that the server provides a poor performance when the load reaches this level, or even cannot cope with such load. Users will see that the server responds very slowly, or doesn't respond at all.

Graphs described in first two cases - flat or gradually growing - can suddenly exhibit a sharp growth. A point where the graph begins to grow sharply is called a performance breakpoint. After this breakpoint, server performance degrades noticeably.

Note that you may use such interpretation of response time graph only if the download time graph doesn't exhibit an essential growth. If the percentage of download time from response time is rather high, it indicates that there are problems with the connection bandwidth, but not with server performance.

Avg response time with page elements: Shows values of average response time for pages including page elements.

Avg processing time: Shows values of processing time averaged through all user profiles. WAPT Pro measures processing time without page elements.

Avg download time: Shows values of download time averaged through all user profiles.

WAPT Pro measures download time without page elements. It is the time of loading the readable content of web page: page structure (frames, tables) and HTML text. In most cases, you will need to know this time rather than download time of all page elements including images, flash movies, etc.

Download time is the measure of web server connection bandwidth. It indicates whether the bandwidth is sufficient to provide a required level of performance or not. If the growth of virtual users number leads to the rapid increase of download time, then most probably your server connection bandwidth is inadequate.

On the whole, you should watch response and download times together. If download time is the major part of response time value, it means that you have problems with the connection bandwidth. You should also analyze other results related to bandwidth: the speed of receiving the information from the server and speed of sending the information to the server.

If Download time graph exhibits sharp fluctuations, you should provide more stable test environment: make your test machine as close as possible to the production server, and conduct tests at off-hours when network traffic is lower.

Sessions per second: Shows the number of sessions executed per time scale unit (second, minute or hour).
Pages per second: Shows the number of pages executed per time scale unit.
Hits per second: Shows the number of hits executed per time scale unit.

The number of pages/hits per second is the most valuable result of testing a site/application capacity and overall performance. If you perform stress testing (testing the site under abnormal or extreme conditions), these graphs will help you find a performance breakpoint.

Active users: Shows the number of virtual users participated in the test.
All: Displays all graphs on this tab.

Bandwidth


Sent: Shows how many kbits per second were sent to the server.
Received: Shows how many kbits per second were received from the server.
Sent per user: Shows the sending speed per virtual user (in kbits per second).
Received per user: Shows the receiving speed per virtual user (in kbits per second).

These graphs will help you know whether the bandwidth of Internet connection to your server is sufficient to provide an acceptable level of performance or not.

Active users: Shows the number of virtual users participated in the test.
All: Displays all graphs on this tab.

Errors


HTTP errors, %: Shows the percentage of responses with HTTP errors from the total number of hits.
Network errors, %: Shows the percentage of responses with network errors from the total number of hits.
Timeouts, %: Shows the percentage of responses with timeouts from the total number of hits.
Total errors, %: Shows the percentage of all responses with errors from the total number of hits.

These graphs will help you know how error rate changes during a test when the number of virtual users is increasing. Error rate is the most valuable result of stress testing where you need to find the maximum number of users that can be served correctly, without errors. You will also need to watch error rate during reliability/endurance tests to verify that it is in acceptable range even after a long run.

You can also view the Errors report for details.

Active users: Shows the number of virtual users participated in the test.
All: Displays all graphs on this tab.

Server Performance


Graphs on this tab show the values of corresponding performance counters.

Memory Usage (%): Shows the percentage of used virtual memory on a specified web server (memory utilization).

Disk Usage (%): Shows the percentage of used disk space on a specified web server (disk utilization).

CPU Usage (%): Shows the load on processor on a specified web server (CPU utilization).

Network Interface Speed (kbit/s): A number of graphs showing the network cards bandwidth (server network interfaces speed) for used interfaces. These graphs will help you know whether the bandwidth of Internet connection to your server is sufficient to provide an acceptable level of performance or not.

All: Displays all graphs on this tab.

SQL Performance

These graphs show values measured by SQL performance counters for a tested database server.

Custom


Custom tab represents all graphs from the previous tabs.

Saving the Summary Graphs


You can save any chart as an image in png format in required location. Select a desired tab, right-click on the chart and select the Save Current Chart to Image... option on the context menu.

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