The Crowd2 plugin is slowing down my instance

I have the Crowd2 Plugin version 1.x installed and it is slowing down my instance. Furthermore, in the logs of the Crowd2 server I can see lots of requests coming from Jenkins.

You should make sure to update the Crowd2 Plugin to at least version 2.0.0. In this version, a cache mechanism was put in place to reduce the number of requests sent by Jenkins.