Re: OL2.3 vs OL2.4 perf issues

[Howard Chu <hyc@symas.com>]

Hallvard B Furuseth wrote:
> Quanah Gibson-Mount writes:
> > OL 2.4 with howard and hallvard's patches: 17,086 auths/second.
>
> I'm tempted to backport the patches to 2.3 so we can compare with
> what 2.3 could have been:-)

Yeah, that thought crossed my mind too. These are both limited-scope patches 
so the backport should be pretty easy.

But right now I'd like to focus on the differences in the 2.3 and 2.4 profile 
results, so we can see where we lost the performance...

> > That still leaves us over 4,500 auths/second (or 9000 searches/second)
> > slower than RE2.3. I.e., 21.5% slower.  Which is quite a substantial gap.
>
> Maybe --disable-debug is a place to fetch some speed.  If it makes a
> enough difference from loglevel 0, it might be an idea to disable _some_
> loglevels and some asserts in the default build.  After we've done
> something about that broken log system of course - IIRC today one needs
> to turn on massive logging to get certain error messages.

Most error messages of any importance are logged at level -1, so they're 
always displayed if any level of logging was enabled. I don't think this 
particular area is really broken. Certainly disabling debug support will give 
a sizeable performance boost, but it will also make diagnostics impossible 
when anything goes wrong.

We can always tell performance-sensitive users to build and install the whole 
thing twice, once without debug, and run that unless they need to reproduce a 
problem... :P

--
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/