openldap 2.1.12 memory utilization ?

while running some load tests with openldap (sub tree search, SASL/GSSAPI binds, TLS) ive seen memory allocated for slapd in 16k increments under the load(i stupidly forgot to measure the connection attempts). after stopping the load tests, i was expecting slapd to release memory it had allocated to handle the load, but it didnt. im testing with a very small db and have plenty of mem to cache the whole db. it would seem to me that slapd should release the mem shortly after it has successfully closed the connection or is something else done by design?