newMatchingRoleMap() is a root method in RoleStrategy#getACL() : https://github.com/jenkinsci/role-strategy-plugin/blob/a2069c1fcb56ff0cd8b80a0655931f5974634eee/src/main/java/com/michelin/cio/hudson/plugins/rolestrategy/RoleBasedAuthorizationStrategy.java#L124 . Its performance is not ideal, because the underlying method creates an intermediate collection for matching roles: https://github.com/jenkinsci/role-strategy-plugin/blob/6b91d9fa597fb6b6766589556aab4ab5d727368e/src/main/java/com/michelin/cio/hudson/plugins/rolestrategy/RoleMap.java#L340 

It would be great to improve performance by refactoring newMatchingRoleMap() and getMatchingRoles() to have an iterator-based RoleWalker logic without intermediate collections