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

[Howard Chu <hyc@symas.com>]

Howard Chu wrote:
> Howard Chu wrote:
> > Howard Chu wrote:
> > > 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.)

> Re-running on Linux with a non-optimized build, peaked at 40,101 auths/sec. (I
> guess HEAD has sped up a bit more in the past week or so...)

OK, this is odd. The code compiled without optimization peaks at 40K auths/sec 
at around 124-132 client threads. The code compiled with -O2 peaks at 37K sec 
at around 128 client threads.

The -O2 build is faster from about 4 to 24 client threads. From 28 on up, the 
nonoptimized code is faster at every load level. I was originally using gcc 
4.1.2 but I'm seeing the same result now using gcc 4.2.2. Also, slapd is only 
configured with 8 worker threads in all of these tests. Strange that whatever 
optimizations the compiler has generated speeds things up for lighter load, 
but works against it under heavier load.
--
  -- 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/