Time to First Buffer Breakdown (Over Time) graph

This graph displays each web page component's server and network time (in seconds) during each second of the load test scenario run, for the period of time until the first buffer is successfully received back from the web server.

Note: This graph is relevant only when the load generator does not use a proxy to connect to the application under test. If the load generator is connected through a proxy, this graph shows only the proxy latency—not the AUT latency.

Purpose

You can use this graph to determine when during the scenario run a server- or network-related problem occurred.
X-axis

Elapsed time from the beginning of the scenario run.
Y-axis

Average network or server time (in seconds) for each component.
Measurements

  • Network time is defined as the average amount of time that passes from the moment the first HTTP request is sent until receipt of ACK.

  • Server time is defined as the average amount of time that passes from the receipt of ACK of the initial HTTP request (usually GET) until the first buffer is successfully received back from the web server.

    • Note: Because server time is being measured from the client, network time may influence this measurement if there is a change in network performance from the time the initial HTTP request is sent until the time the first buffer is sent. The server time displayed, therefore, is estimated server time and may be slightly inaccurate.

Note

  • Each measurement displayed on the page level is the sum of that measurement recorded for each page component. For example, the network time for https://www.anysite.com/ is the sum of the network time for each of the page's components.

  • When the Time to First Buffer Breakdown (Over Time) graph is selected from the Web Page Diagnostics graph, it appears as an area graph.
See also

Web Page Diagnostics graphs overview

Example

You can break down the main cnn.com URL to view the time to first buffer breakdown for each of its components.

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