Peass Demo
This demo repo shows how to detect a simple performance change and its cause by Peass. It contains several demos (pure-demo, spring-boot-demo, android-demo) which show and check the usability of Peass for these type of projects.
The pure-demo contains three versions, where ExampleTest creates an instance of ExampleClazz and calls its method calleeMethod. This method calls Callee.method1 which calls Callee.innerMethod which contains a Thread.sleep. In the 3rd version b6b35a5, Callee.innerMethod contains a longer call to Thread.sleep than before. Therefore, performance gets worse in this version.
If you just want to see the results, you can also immediately open pure-demo/example_results/peass/results/b6b35a5952416a7b1a16b4e90e44ac22d5749af0/de.dagere.peass.ExampleTest_test.html.
Prerequisites
In current development state, it is recommended to use the latest development version of Peass. The following commands require (at least) installed OpenJDK 8, maven and tar and have been tried on Ubuntu 18.04 and 20.04.
For installing the latest development version of Peass run git clone https://github.com/DaGeRe/peass.git && cd peass && mvn clean install -DskipTests -P buildStarter inside the root folder of the project in order to clone and build Peass (optionally add -DskipTests to the mvn-call to speed up building).
To get the example running, untar the example project using tar -xvf demo-project.tar.xz (which is a git project itself and is therefore managed inside this repo as tar). For the following commands, we assume that you are in the peass-folder and that the pure-demo is in the folder one level above.
So you should got:
- peass (in the main folder)
- pure-demo/demo-project
- pure-demo/demo-project.tar.xz
and than run cd peass.
Executing the Regression Test Selection
Run ./peass select -folder ../pure-demo/demo-project (takes ~1 minute). After the selection, you'll find results/execute_demo-project.json, an executionfile for the project, which specifies which tests could have changed performance based on source code analysis.
Executing the Measurement and Getting the Changes
Run ./peass measure -executionfile results/execute_demo-project.json -folder ../pure-demo/demo-project -vms 5 -iterations 5 -warmup 5 -repetitions 5 in order to obtain performance measurements. For real examples, higher execution times are needed, but for the demo case, this is sufficient.
Afterwards, run ./peass getchanges -data ../pure-demo/demo-project_peass/ -dependencyfile results/deps_demo-project.json (takes ~1 second) in order to identify the changes.
Now in results/changes_demo-project.json, all changes are listed. As expected, b6b35a5952416a7b1a16b4e90e44ac22d5749af0 contains a change in ExampleTest.test.
Executing the Root Cause Analysis
Execute ./peass searchcause -vms 3 -iterations 5 -warmup 1 -repetitions 5 -version b6b35a5952416a7b1a16b4e90e44ac22d5749af0 -test de.dagere.peass.ExampleTest\#test -folder ../pure-demo/demo-project -executionfile results/execute_demo-project.json (takes some time) in order to get changes.
To finally get the root cause analysis visualization, run ./peass visualizerca -data ../pure-demo/demo-project_peass/ -propertyFolder results/properties_demo-project/.
Now, results/b6b35a5952416a7b1a16b4e90e44ac22d5749af0 contains the file de.dagere.peass.ExampleTest_test.html which you can visualize in your browser. You'll see that ExampleTest#test, ExampleClazz#calleeMethod, Callee#method1 and Callee#innerMethod are red - therefore, all these have gotten slower and Callee#innerMethod is very likely the root cause of the performance change.
Use the provided shell-script
Instead of running each above step on its own, you can also run executeAll.sh. This will execute the described steps and also test some of the results for correctness.
Spotting Bugs
In case any step did not work, you can check whether the results (both in pure-demo_peass, mostly results for potential remote execution and debugging, and in peass/results, mostly results which are relevant to the developer) look correct. If this does not work, do not hesitate to contact the maintainer.