With the default log settings you would see this in alfresco.log
15:44:56,575 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Synchronizing users and groups with user registry 'lap1'
15:44:56,575 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Retrieving users changed since 18-Jun-2009 13:45:34 from user registry 'AUTH.EXT.lap1'
15:44:56,966 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Updating user 'dward'
15:44:56,981 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Updating user 'hippo'
15:44:56,997 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Updating user 'fullname'
15:44:57,012 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Updating user 'walrus'
15:44:57,028 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Updating user 'platypus'
15:44:57,044 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Updating user 'emu'
15:44:57,059 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Creating user 'koala'
15:44:57,403 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Updating user 'kangaroo'
15:44:57,419 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Creating user 'hippo2'
15:44:57,669 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Retrieving groups changed since 18-Jun-2009 13:30:59 from user registry 'AUTH.EXT.lap1'
15:44:57,716 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] Finished synchronizing users and groups with user registry 'AUTH.EXT.lap1'
15:44:57,716 INFO [org.alfresco.repo.security.sync.ChainingUserRegistrySynchronizer] 9 user(s) and 3 group(s) processed