LoadRunner的工作原理(第一部分)

Architecture Overview LoadRunner works by creating virtual users who take the place of real users operating client software, such as Internet Explorer sending requests using the HTTP protocol to IIS or Apache web servers. Requests from many virtual user clients are generated by "Load Generators" in order to create a load on various servers under test These load generator agents are started and stopped by Mercury's "Controller" program. The Controller controls load test runs based on "Scenarios" invoking compiled "Scripts" and associated "Run-time Settings". Scripts are crafted using Mercury's "Virtual user script Generator" (named "V U Gen"), It generates C-language script code to be executed by virtual users by capturing network traffic between Internet application clients and servers. With Java clients, VuGen captures calls by hooking within the client JVM. During runs, the status of each machine is monitored by the Controller. At the end of each run, the Controller combines its monitoring logs with logs obtained from load generators, and makes them available to the "Analysis" program, which can then create run result reports and graphs for Microsoft Word, Crystal Reports, or an HTML webpage browser. Each HTML report page generated by Analysis includes a link to results in a text file which Microsoft Excel can open to perform additional analysis. Errors during each run are stored in a database which can be read using Microsoft Access

Virtual Users (Vusers) Unlike a WinRunner workstation which emulates a single user's use of a client, LoadRunner can emulate thousands of Virtual Users. Load generators are controlled by VuGen scripts which issue non-GUI API calls using the same protocols as the client under test. But WinRunner GUI Vusers emulate keystrokes, mouse clicks, and other User Interface actions on the client being tested Only one GUI user can run from a machine unless LoadRunner Terminal Services Manager manages remote machines with Terminal Server Agent enabled and logged into a Terminal Services Client session. During run-time, threaded vusers share a common memory pool. So threading supports more Vusers per load generator. The Status of Vusers on all load generators start from "Running", then go to "Ready" after going through the init section of the script. Vusers are "Finished" in passed or failed end status. Vusers are automatically "Stopped" when the Load Generator is overloaded. No additional license is needed to monitor standard web (HTTP) servers (Apache, IIS, and Netscape). To use Web Services Monitors for SOAP and XML, a separate license is needed, and vUsers require the Web Services add-in installed with Feature Pack (FP1)

Product Versions Version 8.1 Feature Pack 4 patch installer LR81FP4P136.exe at 7,786,800 bytes, was signed on January 2, 2007 as file 8.1.4.0 (Build: 1735) is Recorder Version: 1290. Version 8.1 Feature Pack 4 installer LR81FP4.exe, at 194,644,720 bytes, was signed on December 15, 2006 as file version 8.1.4.0 (Build: 2249) is Recorder Version: 1289. This requires an upgrade to MS.NET 2.0 clients. Version 8.1 Feature Pack 3 installer LR81FP3.exe, at 116,601,240 bytes, was signed on June 18, 2006 as file version 8.1.3.0 (Build 2085). It installs (as an item on your Start > Program Files) Microsoft WSE (Web Services Enhancements) 2.0 SP3 to deploy security policies for sytems running .NET Framework 1.1. Version 8.1 became available October 2005. In VuGen it adds a "Workflow View", "Workflow Wizard", and a memory leak which is fixed with a patch downloadable since Dec. 2005. It renames the VuGen "Execution Log" the "Replay Log". Version 8.0 became available August 2004. It adds "Additional Attributes" to Runtime Settings. It also adds (for additional fee) diagnostics and tuning capabilities, allowing Transaction Breakdown to breakdown transaction times across different servers servicing various transaction layers (web server, Oracle 11i & Peoplesoft 8 app server, database) layers. It separates SQL time in execute, parse, and fetch times. Version 7.8 Feature Pack 1 added support for Windows XP. Version 7.8 became available September 2003. Version 6.5 available June 2000 offered new "TurboLoad" technology -- a completely new replay engine that runs thousands of vusers using a single operating system thread. Version 6.0 used a separate thread per user, which required almost 10 times more i/o and CPU cycles than 6.5.

Note: Links to documents that used to be here were removed after Mercury Interactive, Inc. lawyers demanded their removal. Page numbers in online pdf files are different (have more pages) than page numbers in the paper document of the same title.

Application Components' Requirements Loadrunner makes use of four executables with different system requirements Application Product Process Image Name V8.0 Img KB File Size - LRLauncherApp.exe 16,288 n/a Virtual User Generator VuGen.exe 12,436 2,334,769 Controller with On-Line Monitors wlrun.exe 13,076 5,681,215 Load Generator Agent magentproc.exe 3,236 magentservice.exe 65,536 mdrv.exe Analysis Analysisui.exe 13,132 6,058,496 Tuning Console protune.exe 3,403,833

Console programs perl5.8.0.exe Interpreter 20,535 regtlb.exe registers the batch automation type library 30,720 sed.exe 55,296 wdiff.exe Compares text files 197,632 Alex Arbitman's LR 7.8 Footprints.xls reports that to run Web requires __ per process and __ per thread.

Using Windows Remote Desktop Connection Remote Desktop Connection (part of the Terminal Services that comes with Winodows XP) is not as reliable with LoadRunner as Remote Administrator. To keep Windows Remote Desktop Connection sessions from timing out during a test, the Terminal Services on each machine should be configured as follows: Click Start, point to Programs (or Control Panel), Administrative Tools and choose Terminal Services Configuration. Open the Connections folder in tree by clicking it once. Right-click RDP-Tcp and select Properties. Click the Sessions tab. Make sure "Override user settings" is checked. Set Idle session limit to the maximum of 2 days instead of the default 2 hours. Click Apply. Click OK to confirm message "Configuration changes have been made to the system registry; however, the user session now active on the RDP-Tcp connection will not be changed." Make sure that when you do this you're not violating one of your corporation's security policies. Terminal Server only allows two simultaneous connections. To disconnect from a session, do not click "X" on the remote desktop window but click Start and Log Off.

Quality Web Systems: Performance, Security, and Usability (Addison-Wesley Professional; Aug. 2001) by Elfriede Dustin, Jeff Rashka, Douglas McDiarmid The Web Testing Handbook (S T Q E Pub, Jan. 2001) by Steven Splaine, Stefan P. Jaskiel, Alberto Savoia is a good overview introduction, but does not make you an expert.

Among Common problems installing LoadRunner: Windows 2003 & XP SP2 have a DEP (Data Execution Prevention) feature which prevents VuGen recording. Go to Control Panel, System -> Advanced tab, Performance section "Settings" button Data Execution Prevention tab and add the client program or choose "Turn on DEP for essential windows programs and services only." A reboot is required. LR Installation and Configuration Download [after required registration] the 10 day trial from here or here. I recommend that you put downloaded LoadRunner installation files and patches to a separate media such as a CD or USB drive. Then mark those files as read-only. Disable your anti-virus software (Symantec, McAfee, etc.) before invoking on installers. Virus Detection engines (such as Hauri versions since May 18) may find that program regtlb.exe (which registers/unregisters type libraries) to contain a "virus" they call "Backdoor.Win32.PoeBot.15872". Automatic repair by the virus remover will break those files. The LR box comes with two CD's and this installation manual. Separate installation manuals are available for the Controller and Analysis modules. The Windows CD autostarts to this initial screen for v7.8 and this initial screen for v8.0 You can install just a single component (such as VuGen) by (ironically) selecting "Full install" and then the "Custom" option to check the specific components to install. However, due to a strange bug with v8.0, before you do that, first install the Load Generator, then return to install "custom" components. The UNIX CD installs only the Load Generator (not the Controller or VuGen) on UNIX machines because the Controller and VuGen only run on Windows machines. Zero fill machine names to t001, ... t010, etc. The LR Controller sorts machines named t1, t2, ... t10 as t1, t10, t2. Location of Program Files The LoadRunner installation program adds files in Program Files, Windows folder, and the Windows Registry that are NOT removed during un-installation. If you get a "License violation" message, you need to get from Mercury support a one-day license key to install with. By default, different versions of LoadRunner are installed to different parts of your hard disk: LoadRunner 8.1 executable files are installed to file path "C:\Program Files\Mercury\LoadRunner\bin" LoadRunner 8.0 "stutters" when it installs to its default file path "C:\Program Files\Mercury Interactive\Mercury LoadRunner\bin" Note: Even though 8.0 uses a different folder, folders created by previous versions still need to be removed before its installation. LoadRunner 7.8 executable files are installed to file path "C:\Program Files\Mercury Interactive\LoadRunner\bin" When working with Java, instead of overridding these default installation folder to a path without spaces (such as C:\LR78) as recommended by KB article 11878, just use the equivalent DOS 8.3 file names: For LoadRunner 8.1: C:\PROGRA~\MERCUR~1\LoadRunner\lib For LoadRunner 8.0: C:\PROGRA~\MERCUR~1\MERCUR~1\lib To quickly get at this LoadRunner installation folder, create an environment variable named "LR81" so you can use a quick command such as cd %lr81% To get at this folder quickly, I created a batch file named "L.bat" in the cmd's default C:\ root folder containing this: cd \Program Files\Mercury\LoadRunner\bin pause I created a shortcut to this file on my desktop and dragged it over Windows so that I can click into that folder from anywhere. The pause command ensures that the command window does not disappear automatically. Alternately, from within a command window I can just type "L" and press Enter. Files in Windows Folders This path specified is stored under [ProductEnv] as M_ROOT in file wlrun.ini in the C:\WINNT (or C:\Windows) folder. The C:\WINNT (or C:\Windows) folder also holds the Maintenance Number (MPN) specified during installation, stored as a parameter named "LoadRunner_SerialNumber" (such as 1234-1234567890) in the mercury.ini file. Start Menu The LR installer adds links to the most used programs in > Programs > Mercury Interactive > LoadRunner However, some programs are installed which are not conveniently listed there, such as WDiff.exe v1.49 to compare differences between two ASCII text files. It has an accompanying help file Beginning with v7, LoadRunner prevents software piracy (much like Microsoft began doing with Windows XP) by requiring that a license key be provided within 10 days of installation. Mercury generates its license key based on a host ID generated on each computer. CPT12784.doc With v7.x, to generate Generate a HostID key (such as "XCCWJU-APBE-BYDS") click down Programs > Mercury LoadRunner > LoadRunner > License tab The key can be obtained before installation from program licidgenerator.exe and (after registration) its lm70.dll from the installation CD folder \lrunner\lm70.nt\bin or \lrunner\setup\lm70.nt\bin. Sample Apps / Protocols Running the samples install program populates folder C:\Program Files\Mercury Interactive\Mercury LoadRunner\ Copy the link location below into the "Program to record:" field: Protocol Server Client Program Parameter Notes Web WebTours\StartServer.bat http://localhost:1080/mercuryWebTours COM/DCOM (Operating System) samples\bin\frsui.exe Winsock sockfrs.exe samples\bin\flights.exe Winsock WinSockWeb ODBC (MS Access) samples\bin\flights.exe ODBC_Access CORBA samples\CorbaSamples\server.cmd & samples\CorbaSamples\server.bat samples\CorbaSamples\client.cmd & samples\Corbasamples\clientrecord.cmd Stuart Moncrieff's article on CORBA RMI samples\RMISamples\server.cmd & samples\RMISamples\server.bat samples\RMISamples\client.cmd & samples\RMISamples\clientrecord.cmd According to CPT11877.doc, JDK 1.5 users need to contact Mercury Support for a patch to each specific LoadRunner version (7.6, 7.8 FP1 or 8.0). Otherwise, you'll get these messages: Error: Failed to find javac.exe Java Compiler in Path and JDK installation folder in registry. [MsgId: MERR-22981] Error: Failed to compile the Actions.java file. Please add the \bin to the path and try again. [MsgId: MERR-22996] Warning: Extension java_int.dll reports error -1 on call to function ExtPerProcessInitialize [MsgId: MWAR-10485] Error: Thread Context: Call to service of the driver failed, reason - thread context wasn't initialized on this thread. [MsgId: MERR-10176] The Java sample apps use the "flight32lr" User Data Source with Microsoft Access driver(*.mdb) in the USER DNS table in Data Sources(ODBC) of the VuGen's local machine. Additionally, the sample Java servers must be operational prior to starting the client. This is done with the "samples\RMISamples\server.cmd": set lrpath=C:\PROGRA~1\Java\jre1.5.0_02\bin;C:\PROGRA~1\MERCUR~1\MERCUR~1\classes set lrclasspath=C:\PROGRA~1\MERCUR~1\MERCUR~1\classes;C:\PROGRA~1\MERCUR~1\MERCUR~1\classes\srv;C:\PROGRA~1\Java\jre1.5.0_02\lib\rt.jar set flightRmi=%~dp0;%~dp0RmiSamples.zip set classpath=%lrclasspath%;%flightRmi%;C:\PROGRA~1\Java\lib\rt.jar;.;%classpath% set path=%lrpath%;.;%path% cd %~dp0 start java -Djava.security.policy="%~dp0RmiFlights.policy" RmiFlights.Server Note the location of loadrunner class files I added to the default sample. They are pre-pended to the existing classpath. Note that there are no spaces in the file path. The Zip file is equivalent to a JAR file in Unix systems. Do not delete the black command window because the Java server runs within it. CORBA and RMI Java clients are invoked with a command for Windows to start the java.exe program. This "samples\RMISamples\client.cmd" file contains: set lrpath=C:\PROGRA~1\Java\jdk1.5.0_02\bin;C:\PROGRA~1\MERCUR~1\MERCUR~1\classes set lrclasspath=C:\PROGRA~1\MERCUR~1\MERCUR~1\classes;C:\PROGRA~1\MERCUR~1\MERCUR~1\classes\srv;C:\PROGRA~1\Java\jdk1.5.0_02\lib\rt.jar set flightRmi=%~dp0;%~dp0RmiSamples.zip set classpath=%lrclasspath%;%flightRmi%;C:\PROGRA~1\Java\jdk1.5.0_02\lib\rt.jar;.;%classpath% set path=%lrpath%;.;%path% cd %~dp0 start java RmiFlights.main Note that the RmiFlights.main class file name is passed into java for it to load. When recording Java with VuGen, a different command — such as the sample clientRecord.cmd — needs to be invoked because VuGen needs to be invoked within the JVM sandbox: set flightRmi=%~dp0;%~dp0RmiSamples.zip set classpath=%flightRmi%;%classpath% cd %~dp0 start InvokeVugen.exe The location of the JDK needs to be specified in the Windows PATH environment variable PATH to avoid this message: Error: Failed to find javac.exe Java Compiler in Path and JDK installation folder in registry. [MsgId: MERR-22981] VuGen "Java Vusers" can only operate as Single Vuser mode (not multi-vuser). Instead of web "Start recording", Java VuGen scripts invoke Java functions within the Actions section. "vuser_init" and "vuser_end" actions are not relevant within Java VuScripts. Internally, the cjhook.ini file specifies which Java classes can hook in its [EXC_SYSTEM_CL] section. Java classes specified in the [SYSTEM_CL] section are not hooked. The user.hooks file in LR \bin folder is a general format and cannot be used as-in. It needs to be copied. Uninstall To uninstall LoadRunner, you must be logged in with the same Windows userID as was used during original installation! If you use a different userid, the uninstall will delete only the dat folder which contains the "miuninst" file. Unlike Microsoft Office applications, Mercury has not programmed invididual components to be selectively uninstalled on its own.