openldap bench / stress free tools

[Jehan PROCACCIA <Jehan.Procaccia@int-evry.fr>]

hello,
some users complain that my openldap server is "slow", when using 
outlook clients in the address book , it apparently often happens that 
it times out on openldap searchs so then it goes to the AD addressbook :-( .
Is there a free and simple tools to check the performances of my 
openldap servers ?
I use a very rudimentary bench with time and ldapsearch but is there a 
better solution , avoiding cache for example ?
$ time ldapsearch -x cn=*la* -h ldap1.int-evry.fr sn mail -L
# numEntries: 381
real    0m0.447s
user    0m0.020s
sys     0m0.012s
$ time ldapsearch -x cn=*la* -h ldap2.int-evry.fr sn mail -L
# numEntries: 381
real    0m1.940s
user    0m0.064s
sys     0m0.036s

thanks