Re: commit: ldap/servers/slapd connection.c daemon.c proto-slap.h syncrepl.c

[Howard Chu <hyc@symas.com>]

hyc@OpenLDAP.org wrote:
> Update of /repo/OpenLDAP/pkg/ldap/servers/slapd
>
> Modified Files:
> 	connection.c  1.410 -> 1.411
> 	daemon.c  1.414 -> 1.415
> 	proto-slap.h  1.743 -> 1.744
> 	syncrepl.c  1.370 -> 1.371
>
> Log Message:
> Streamlined Winsock connection management

This patch eliminates all the #ifdef WINSOCK special cases in connection.c, 
and hides most of the dependencies in daemon.c.

Winsock's select() implementation is pretty non-optimal. Unfortunately using 
the Microsoft-recommended asynchronous functions would implicitly set all the 
sockets to non-blocking, and stuff like OpenSSL doesn't behave well with 
non-blocking sockets.

For reference, the peak throughput with back-null on the previous code was 
only 7,800 auths/sec (with 8 client threads). With this patch it's 11,140 
auths/sec. In both cases the throughput declines as more client threads are 
used. (Compare to 35,553 auths/sec for the same machine running Linux, and no 
drop in throughput all the way up to hundreds/thousands of connections.)

Peak throughput on the new code with back-hdb is 7,972 auths/sec (with 12 
client threads). With the previous code it was 6,252 auths/sec (with 8 client 
threads). (The 7,972 figure is also after setting processor affinities for the 
threads, forcing the listener to use core #0 and forcing the worker threads to 
use cores #1-7. Without that tweak, the peak is only 7,717/sec.)
--
  -- Howard Chu
  Chief Architect, Symas Corp.  http://www.symas.com
  Director, Highland Sun        http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP     http://www.openldap.org/project/