The traffic model we are testing contains search and modify operations. The search response contains usually a single entry about 3KB in LDIF format. There is only a reduce number of LDAP clients (usually one or two), that are using async LDAP API and sending a lot of operations per second (> 1000 TPS per client). The client side is an OS Delta box.
Under these conditions we have tested that increasing the sending buffer of the server has improved the performance. That's the reason I am proposing this feature request.
Pierangelo's proposal allowing hard-set the buffer sizes looks ok.
A patch is in HEAD. Please test. It is enabled by default when LDAP_DEVEL is set (namely, when building HEAD). The patch may need some work on architectures different from Linux.
p.