Currently RoleMap has no caching for SIDs though all performance requests actually operate with SIDs. Each time the permissions is checked, all matching roles have to be checked for SIDs: https://github.com/jenkinsci/role-strategy-plugin/blob/role-strategy-2.9.0/src/main/java/com/michelin/cio/hudson/plugins/rolestrategy/RoleMap.java#L107 

Extra caching could help in the case of the cases when there are many roles defined in the RoleMap. 

Such caching needs to be aware of potential security concerns, and there should be proper invalidation