Module.addExportedPaths degrades in performance on 1.6+ after MODULES-256. This could become noticeable in a case of more complex/numerous modules+dependencies and is something I saw remaining for similar cases after resolving WFCORE-6188. It's noteworthy there is no impact on EAP 7.0.9 (around ~10 second start with attached test app) and 7.1.0+ degrades to 30+ seconds with MODULES-256.

From thread dumps and a JFR, I can see it is spending more times in call stacks like:

java.lang.String.offsetByCodePoints
org.jboss.modules.ModuleIdentifier.toString()
org.jboss.modules.ModuleLoader.loadModuleLocal
org.jboss.modules.ModuleLoader.preloadModule

And:

java.lang.String.hashCode
org.jboss.modules.ModuleIdentifier.calculateHashCode
org.modules.ModuleIdentifier.<init>
org.jboss.modules.ModuleIdentifier.fromString
org.jboss.modules.ModuleLoader.preloadModule

For repeating dependencies, these could repeat the same calls a lot for recurring overhead.