You can use Infinispan (the successor of JBossCache) in two modes

client-server

here Infinispan is a separate instance

embedded

the infinispan is within the same JVM as JBoss

both modes have different benefit.

You should start with the docs and examples here Infinispan Homepage - Infinispan

Regarding performance, the cache can boost your application performance, but it depends on your use-case.

As a rule of thumb, as slower your database or backend is as more a cache will help

It is not related to the OS.

You might have a look to the Tutorials or my example how to run inside of EAP, which is slightly different but should explain how you can use it for Wildfly/Infinispan