Use IBM page detailer to analyze Web Application Performance and Tuning

This document introduces the functions and usage of IBM page detailer, and uses an example to demonstrate how to analyze the results obtained by IBM page detailer and provide suggestions for improving the web application performance.

Introduction

In the daily work of performance testing, testers often need some tools to provide us with data for analysis. Selecting effective tools often results in a better test effort. During the analysis of Web application performance, testers need to obtain data related to network transmission. For the acquisition of underlying information, many existing tools can provide data at the data packet level. However, when testers need to analyze further data, the information provided by these tools is often too complex and inconvenient for the analysis process. In this case, we recommend using IBM page detailer to improve productivity.

IBM page detailer was developed by two senior engineers at the IBM Research Institute, Leroy Krueger and Nat Mills. This is a software used to measure the performance of Web applications. Because it is designed from the perspective of customer experience, it is more conducive to adjusting the performance of Web applications based on the collected data, better meet customer needs to achieve better customer satisfaction.

IBM page detailer supports Windows 2000, XP, Server 2003, and Windows Vista operating systems, which are divided into basic and pro versions. The basic installation files can be downloaded from IBM alphaWorks.

Basic is a free trial version and has certain functional limitations. The Pro version has the following enhanced functions:

• Full support for HTTPS (SSL) Communication
• Data can be saved and imported for retrieval.
• Export data in XML format
• Tagging
• Search for text processing in event view
• Image Display

All examples in this article take the Pro version as an example.

IBM page detailer inserts a probe into the Windows Port stack of the client to obtain relevant information. For Microsoft Internet Explorer, Mozilla Firefox and some Netscape browsers, the probe is automatically activated without configuration. When using other types of browsers, you can modify the wd_ws2s.ini file in the installation directory to activate the probe, for specific modification methods, refer to the section "using page detailer with other applications" in the Help file.

IBM page detailer can obtain the following types of data:

• Total connection time
• Port connection time and data volume transmitted
• SSL connection time and data volume
• Server Response Time and data volume transmitted
• Content transfer time and data volume
• Transmission Delay Time
• Request byte header
• Request Data Transmission
• Feedback byte header
• Feedback data content
• Total number of pages, average, maximum, and minimum number of pages

IBM page detailer provides a wide array of legends (see figure 1). Different colors and icons are used to represent different states and elements, allowing data to be clearly displayed and convenient for analysis.

Figure 1. Legend

IBM page detailer provides two views: Chart view and Detail View. In the Chart view (see figure 2), the download time, number of bytes, and total number of elements on each page are displayed, in addition, color bars of the corresponding color are used to represent the transmission process of each element and the proportion of the download time of the entire page according to the actual Transmission sequence. The overlapping part indicates that the download of these elements is completed in parallel.

Figure 2. Chart view

The chart view displays the download overview of each page from a global perspective. To learn more about each element on the page, go to the Details View.

Figure 3. Detail View

The default column in the Detail View (see figure 3) Only displays the element name, download time, element size, and element download legend. In addition, you can right-click (as shown in Figure 4) and select Add column to display more required information in the view. This information is automatically collected by the IBM page detailer during data capturing. The required columns are displayed immediately.

Figure 4. Add Detail View column elements

In the two views, double-click the row where the element is located to open the event interface (see figure 5). More HTTP request details are displayed here, this helps testers understand the full information of each element. In this interface, you can also find and add comments.

Figure 5. event page

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Application Instance

Environment Description

The application system is deployed on IBM WebSphere Portal Server and process server. And uses ibm http server (IHS) to cache image files, in order to improve customer access efficiency and shorten response time.

• Install ibm http server on IBM WebSphere Portal Server and enable cache.
• Use the IBM page detailer client to record the data on the same page for the first access and subsequent access, and compare and analyze the data.

First Data Access result

See Figure 6. The item size shows that when you access the application service for the first time, all image files are downloaded to the client.

Figure 6. First Data Access results

Second Data Access result

As shown in figure 7, all images are not downloaded again, and ibm http server plays a role in Image File caching.

Figure 7. Second Data Access result

Further Performance Analysis

We compared the response time of each page in the two test results, and found that the performance was not significantly improved. In the application, the initiate domestic page took the most time in both visits. Therefore, we further analyze the data.

On the initiate domestic page, the compressed HTML occupies a large proportion of the transmission time. Double-click this element and open the event window to view detailed HTTP request information. As shown in figure 8, the time is mainly consumed by the response of the SSL server, accounting for about 99.5% of the total time. The response time of the SSL server starts from when the client sends a request until it receives the first response packet from the server.

Figure 8. Initiate domestic page SSL server response

The ibm http server image cache does not significantly improve performance, and we also find the cause from the data comparison. Although there are many page image elements in the application system, the transmission time on the client and server is very short because the number of bytes of the image is too small (see figure 9 ). Therefore, the image cache provided by ibm http server does not significantly improve access performance.

Figure 9. Image Size and transmission time

In the analysis of other pages (see figure 10), we found that when sending the same amount of request information to the server, the SSL server response time for some pages is short, therefore, developers are advised to address the issue that the initiate domestic page response takes a long time.CodeTo improve the performance.

Figure 10. SSL server response on another page

In addition, through data analysis, we also found that image files on various pages are transmitted using the SSL protocol. Because the image itself does not contain the information to be protected, using SSL protocol for transmission will increase the transmission load to a certain extent. We recommend that you do not transmit the image in encrypted form.

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Summary

In general, as a tool developed from the user perspective, IBM page detailer can help testers master a large amount of data on Web application performance to analyze performance issues, is an indispensable tool in Web application performance testing.

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