Add a Gradle profiler scenario and some instructions

CONTRIBUTING.md

@@ -564,6 +564,23 @@ To be able to benefit from the remote cache, you need to use a Java version test
 The local cache is stored in the `~/.m2/.gradle-enterprise/build-cache/` directory.
 If you have problems with your local cache, you can delete this directory.
 
+During the experiment phase, there might be a need to benchmark the build in a reliable manner.
+
+For this, we can use the [Gradle Profiler](https://github.com/gradle/gradle-profiler).
+It can be installed with SDKMAN! (`sdk install gradleprofiler`) or Homebrew (`brew install gradle-profiler`).
+
+Then we can run the following commands at the root of the Quarkus project:
+
+```
+# Without cache
+gradle-profiler --maven --benchmark --scenario-file build.scenario clean_install_no_cache
+
+# With cache
+gradle-profiler --maven --benchmark --scenario-file build.scenario clean_install
+```
+
+Simple HTML reports will be published in the `profile_out*` directories.
+
 ## Release your own version
 
 You might want to release your own patched version of Quarkus to an internal repository.

build.scenario

@@ -0,0 +1,40 @@
+clean_install {
+    tasks = ["clean","install","-Dquickly", "-T6"]
+    cleanup-tasks = ["clean"]
+    maven {
+        targets = ["clean","install","-Dquickly", "-T6"]
+    }
+    warm-ups = 1
+    iterations = 3
+}
+
+clean_install_no_scan {
+    tasks = ["clean","install","-Dquickly", "-T6", "-Dscan=false"]
+    cleanup-tasks = ["clean"]
+    maven {
+        targets = ["clean","install","-Dquickly", "-T6", "-Dscan=false"]
+    }
+    warm-ups = 1
+    iterations = 3
+}
+
+clean_install_no_cache {
+    tasks = ["clean","install","-Dquickly", "-T6", "-Dno-build-cache"]
+    cleanup-tasks = ["clean"]
+    maven {
+        targets = ["clean","install","-Dquickly", "-T6", "-Dno-build-cache"]
+    }
+    warm-ups = 1
+    iterations = 3
+}
+
+clean_install_no_cache_no_scan {
+    tasks = ["clean","install","-Dquickly", "-T6", "-Dno-build-cache", "-Dscan=false"]
+    cleanup-tasks = ["clean"]
+    maven {
+        targets = ["clean","install","-Dquickly", "-T6", "-Dno-build-cache", "-Dscan=false"]
+    }
+    warm-ups = 1
+    iterations = 3
+}
+