Performance/Automated Tests

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The Eclipse performance test plugin (org.eclipse.test.performance) provides infrastructure for instrumenting programs to collect performance data and to assert that performance doesn't drop below a baseline. The infrastructure is supported on Windows, Linux, and MacOS X.

The first part of this document describes how performance tests are written and executed, the second part explains how performance data is collected in a database and how this database is installed and configured.


Writing Performance Tests

Setting up the environment

  • check out the following plug-ins from
    • org.eclipse.test.performance
    • org.eclipse.test.performance.win32 (for Windows only)
  • you need org.junit
  • add org.eclipse.test.performance to your test plug-in's dependencies

Writing a performance test case

A performance test case is an ordinary JUnit test TestCase. Create a test case with test methods along the lines of:

public void testMyOperation() {
	Performance perf= Performance.getDefault();
	PerformanceMeter performanceMeter= perf.createPerformanceMeter(perf.getDefaultScenarioId(this));
	try {
		for (int i= 0; i < 10; i++) {
 	} finally {

or create a test case extending PerformanceTestCase which is a convenience class that makes the use of PerformanceMeter transparent:

public class MyPerformanceTestCase extends PeformanceTestCase {
	public void testMyOperation() {
		for (int i= 0; i < 10; i++) {


  • The scenario id passed to createPerformanceMeter(...) must be unique in a single test run and must be the same for each build. This enables comparisons between builds. The Performance#getDefaultScenarioId(...) methods are provided for convenience.
  • PerformanceMeter supports repeated measurements by multiple invocations of the start(), stop() sequence. The call to commit() is required before evaluation with assertPerformance() and dispose() is required before releasing the meter.
  • The first iterations of the above for-loop will generally take more time, because the code is not optimized by the JIT compiler yet. This can introduce some variance to the measurements, especially if other tests run before and change in some way that affects the JIT's optimization of the measured code. A simple way to stabilize the measurements is to run the code a few times before the measurements start. Caches also need special caution as they can affect the measurements.
  • As a rule of thumb the measured code should take at least 100 ms on the target machine in order for the measurements to be relevant. For example, Windows' and Linux 2.4's system time increases in 10 ms steps. In some cases the measured code can be invoked repeatedly to accumulate the elapsed time, however, it should be kept in mind that JIT could optimize this more aggressively than in real-world scenarios.

Participating in the performance summary (aka "Performance Fingerprint")

If the number of performance tests grows large, it becomes harder to get a good overview of the performance characteristics of a build. A solution for this problem is a performance summary chart that tries to condense a small subset of key performance tests into a chart that fits onto a single page. Currently the performance infrastructure supports two levels of summaries, one global and any number of "local" summaries. A local summary is typically associated with a component. A summary bar chart shows the performance development of about 20 tests relative to a reference build in an easy to grasp red/green presentation.

FP I200409240800 I200410050800.jpeg

So dependent on the total number of components every Eclipse component can tag one or two tests for inclusion in a global and up to 20 for a local performance summary. Tests marked for the global summary are automatically included for a local summary.

Marking a test for inclusion is done by passing a performance meter into the method Performance.tagAsGlobalSummary(...) or Performance.tagAsSummary(...). Both methods should be called outside of start/stop calls, but it must be called before the the call to commit().

// ....
Performance perf= Performance.getDefault();
PerformanceMeter pm= perf.createPerformanceMeter(perf.getDefaultScenarioId(this));
perf.tagAsGlobalSummary(pm, "A Short Name", Dimension.CPU_TIME);
try {
	// ...

In order to keep the overview graph small, only a single dimension (CPU_TIME, USED_JAVA_HEAP etc.) of the test's data is shown and only a short name is used to label the data (instead of the rather long scenario ID). Both the short label as well as the dimension must be supplied in the calls to tagAsGlobalSummary and tagAsSummary. The available dimensions can be found in org.eclipse.test.performance.Dimension.

The PerformanceTestCase provides similar methods that must be called before startMeasuring():

public class MyPerformanceTestCase extends PerformanceTestCase {
	public void testMyOperation() {
		tagAsSummary("A Short Name", Dimension.CPU_TIME);
		for (int i= 0; i < 10; i++) {

Running a performance test case (from a launch configuration)

  • Create a new JUnit Plug-in Test launch configuration for the test case.
  • Add -Xms256M -Xmx256M or similar to the VM arguments to avoid memory pressure during the measurements.
  • Run the launch configuration.
  • By default, the measured averages of the performance monitor are written to the console on commit(). This is suppressed if performance tests are configured to store data in the database (see below).

Running a performance test case (from the command-line)

  • This method is of particular interest if you want to do precise measurements of a specific build.
  • Export the following plug-ins as 'Deployable plug-ins' to the eclipse installation directory (not the 'plugins' directory; choose to deploy as 'a directory structure')
    • org.eclipse.test
    • org.eclipse.test.performance
    • org.eclipse.test.performance.win32 (for Windows only)
    • your test plug-in(s)

Copy the following .bat file and customize it to your needs (Windows)

@echo off
REM Installation paths
SET JVMPATH=c:\jdk\jdk1.4.2_05
REM Paths, relative to ECLIPSEPATH
SET BUILD=I200411050810
SET WORKSPACE=workspace\performance
REM Test
SET TESTPLUGIN=org.eclipse.jdt.text.tests
SET TESTCLASS=org.eclipse.jdt.text.tests.performance.OpenQuickOutlineTest
REM For headless tests use: org.eclipse.test.coretestapplication
SET APPLICATION=org.eclipse.test.uitestapplication
REM Add -clean when the installation changes
SET OPTIONS=-console -consolelog -showlocation
%JVMPATH%\bin\java %JVMOPTIONS% -cp %ECLIPSEPATH%\%BUILD%\startup.jar org.eclipse.core.launcher.Main %OPTIONS% -application %APPLICATION% -data %ECLIPSEPATH%\%WORKSPACE% -testPluginName %TESTPLUGIN% -className %TESTCLASS%

After testing the setup you may want to close other applications to avoid distortion of the measurements.

Running a performance test case (within the Automated Testing Framework on each build)

If the test.xml of your test plug-in already exists and looks similar to the jdt.text.tests' one, add targets similar to those shown below. The performance target is the entry point for performance testing like the run target is for correctness testing.

<!-- This target defines the performance tests that need to be run. -->
<target name="performance-suite">
  <property name="your-performance-folder" value="${eclipse-home}/your_performance_folder"/>
  <delete dir="${your-performance-folder}" quiet="true"/>
  <ant target="ui-test" antfile="${library-file}" dir="${eclipse-home}">
     <property name="data-dir" value="${your-performance-folder}"/>
     <property name="plugin-name" value="${plugin-name}"/>
     <property name="classname" value="<your fully qualified test case class name>"/>
<!-- This target runs the performance test suite. Any actions that need to happen -->
<!-- after all the tests have been run should go here. -->
<target name="performance" depends="init,performance-suite,cleanup">
  <ant target="collect" antfile="${library-file}" dir="${eclipse-home}">
    <property name="includes" value="org*.xml"/>
    <property name="output-file" value="${plugin-name}.xml"/>


Running a performance test case (within the Automated Testing Framework, locally)

  • Modify test.xml as described above.
  • Download a build and its accompanying test framework plug-ins contained in eclipse-test-framework-*.zip
  • Unzip the Eclipse SDK and the eclipse-test-framework ZIP to install your target Eclipse.

(you need Info-ZIP UnZip version 5.41 or later (Windows) installed and added to the path).

  • Export your test plug-in as a 'Deployable plug-in' to the target Eclipse installed above; choose to export as directory structure.
  • Open a terminal or command window and execute the following (on a single line):
java -jar <an eclipse install>/startup.jar
-application org.eclipse.ant.core.antRunner 
-file <target eclipse install/plugins/your test plug-in id_version>/test.xml 
-Dos=<os> -Dws=<ws> -Darch=<arch> -Declipse_home=<target eclipse install>
"-Dvmargs=-Xms256M -Xmx256M"
  • The JUnit results are written to an XML file in the root of the target Eclipse and the performance measurements are written to the console.

Setting up the Derby database

Performance tests are only valuable if measured data can be monitored over time and compared against reference data. For this functionality the Eclipse performance plugin makes use of the Apache project's Derby database (formerly called Cloudscape). Derby is a database engine written in Java that can be accessed via JDBC. Derby is easily embeddable in Java programs or can run as a network server.

This section describes how to install Derby and how to configure the performance test plugin to use Derby.

Getting and installing Derby

The performance infrastructure does not include Derby. If you want to leverage Derby, you need to download and install it.

The performance plugin has an optional prereq for a org.apche.derby library project. Since it is optional, you won't see any compile time errors when loading the performance plugin from the Eclipse repository and the Derby project is not available in your workspace. However you'll see runtime errors when running the tests and trying to access the database.

If you have access to the following repository you can get the org.apache.derby library project from there:

Otherwise get Derby from here. Unpack the archive to any directory.

To create a library project for Derby, open the Java project wizard and enter org.eclipse.derby as the project's name. Go to the next page and select the Libraries tab. Remove the JRE and add the five JAR-files from Derby's lib directory via the Add External JARs button. Switch to the Order and Export tab and check all five libraries. Press Finish. Create a new file plugin.xml inside the Derby project and paste the following contents into it:

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.0"?>
      <library name="db2jcc.jar">
         <export name="*"/>
      <library name="db2jcc_license_c.jar">
         <export name="*"/>
      <library name="derby.jar">
         <export name="*"/>
      <library name="derbynet.jar">
         <export name="*"/>
      <library name="derbytools.jar">
         <export name="*"/>

In addition you'll need to load the performance plugin (org.eclipse.test.performance) and if you are running on Windows the associated fragment (org.eclipse.test.performance.win32).

Configuring the performance plugin for using Derby

The performance test plugin is configured via the three Java properties eclipse.perf.dbloc, eclipse.perf.config, and eclipse.perf.assertAgainst.

The eclipse.perf.dbloc specifies where the Derby DB is located. If no value is given


Derby runs in embedded mode (not as a separate server) and the DB will live in your home directory.

If an absolute or relative path is given, Derby uses or creates the DB in that location. E.g., with (Linux and Mac OS X)


Derby runs in embedded mode and creates the database under /tmp/derby.

To connect to a Derby server running locally (or remotely) use the following:

-Declipse.perf.dbloc=net://tcp-ip address

With the properties eclipse.perf.config and eclipse.perf.assertAgainst you specify the name under which performance data is stored in the database and the name of the reference data to compare against. This "name" is not a single string but a set of key/value pairs separated by semicolons:


The key/value pairs can be used to associate the collected performance data with information about the configuration that was used to generate the data. Typically this includes the name of the build, the system on which the test were run, or the used Java VM. So in this example:


performance data for the nightly build N20040914 is stored in the database under a "name" that consist of three key/value pairs. If the tests are run multiple times with the same arguments, the new data does not replace old data but is added under the same name. Programs that visualize the data are expected to aggregate the data for example by calculating the average of all tests.

To assert that performance data collected for another build does not degrade with respect to some reference data the assertAgainst property is used similarly:


This property enables any "assertPerformance" calls in your performance tests and compares the newly measured data against the data specified by the three key/value pairs. Please note that the order of the pairs does not matter when looking up the data in the database. However, the number of key/value pairs must be identical.

Because in most cases you want to store newly collected data as well as assert against other reference data at the same time you'll need to specify both properties. In this case only those key/value pairs must be listed in the assertAgainst property, that differ from the config property:


So in the example from above the new performance data is stored in the database under the build name "N20040914" and the host "relengwin" and the "assertPerformance" compares this data against data tagged with a build name of "R3.0" and an implicitely specified host "relengwin".

If you want to assert the average of multiple runs (instead of the data of a single run) against the reference data, do the following:

// Run program 4 times to collect data under build name "I20040914"
... -Declipse.perf.config=build=I20040914
... -Declipse.perf.config=build=I20040914
... -Declipse.perf.config=build=I20040914
... -Declipse.perf.config=build=I20040914
// Run program a 5th time and collect more data under I20040914
// and assert the average of 5 runs of I20040914 against some baseline data
... -Declipse.perf.config=build=I20040914 -Declipse.perf.assertAgainst=build=R3.0

Viewing the data

Since we do not (yet) have fancy visualization tools, the performance test plugin provides a class org.eclipse.test.internal.performance.db.View that can be run as a standalone program for viewing the data contained in the database in a tabular format.

You need to specify the database location via the eclipse.perf.dbloc property (most easily done via a launch configuration). Select the data to view by either specifying a variation via the eclipse.perf.config property or by directly setting the key/value pairs of the variation at the beginning of the program's main method. If you only want to view specific scenarios, use an appropriate pattern for the local variable scenarioPattern. The local variable seriesKey specifies what variation is shown on the x-axis of the table.

So the following setup:

public class View {
    public static void main(String[] args) {
        Variations variations= PerformanceTestPlugin.getVariations();
        variations.put("host", "relengwin");
        variations.put("build", "I%");
        String scenarioPattern= "%RevertJavaEditorTest%";
        String seriesKey= "build";
    	// ...

creates a table showing all dimensions of the (single) scenario selected by the pattern %testRevertJavaEditor% for all integration builds (that is builds starting with a capital 'I').

Scenario: org.eclipse.jdt.text.tests.performance.RevertJavaEditorTest#testRevertJavaEditor()
Builds:              I200409240800    I200409281200  I200410050800  I200410190941  I200410260800
CPU Time:          1.02 s [284 ms]  1.05 s [327 ms]         971 ms            1 s         481 ms
Committed:              69K [246K]      119K [389K]           103K           111K         -97484
Elapsed Process:   1.02 s [286 ms]  1.07 s [345 ms]         981 ms         1.01 s         481 ms
Kernel time:         41 ms [27 ms]    48 ms [40 ms]          46 ms          28 ms          22 ms
Page Faults:             145 [125]        148 [125]            176            191            143
System Time:       1.02 s [285 ms]  1.06 s [345 ms]         981 ms         1.01 s         477 ms

If you are interested in creating performance charts and tables similar to those available on the eclipse platform download pages, you could try the stand-alone java program org.eclipse.test.performance.ui.Main stored in the eclipse.platform.releng.buildtools] repo. Refer to the readme.html in org.eclipse.test.performance.ui bundle for more details.

How to setup a Derby server (on Linux and Mac OS X)

  • Either get Derby from the repository or from here.
  • Get the (Bourne) shell script from the scripts folder of org.eclipse.test.performance and install it on the server (rename it to "derby" and make it executable; if you've checked out the file on Windows and copied it to Linux, it might be necessary to convert line delimiters with the dos2unix tool). The script simplifies the usage of the Derby tools - especially starting and stopping the server - because it sets the correct classpath and some important properties.
  • Edit the script and adapt the variables CSLIB, DBROOT, and JAVA to your installation. CSLIB should point to the directory containing the Derby JARs. If you've used the Derby installer, then this is the lib directory inside the Cloudscape 10.0 directory. If you are using the org.apache.derby project from the repository, then this is just the project folder.
  • In a Shell execute
derby start &
to launch the server in background. The server will send this to stdout:
Server is ready to accept connections on port 1527.
to the console.
  • Stop the server with
derby stop