Re: slapd lightweight dispatcher

[Howard Chu <hyc@symas.com>]

Quanah Gibson-Mount wrote:
> I've done a lot of testing in the last several days on a binary with 
> the lightweight dispatcher code enabled (2.3 base), and I just want to 
> say I'm a very big fan of it.  It allows slapd to scale under high 
> load at a rate I've not previously seen.  I've also played with the 
> multi-conn flag as well, and haven't seen it particularly affect the 
> rates when only it is enabled, but I haven't tried the lightweight 
> dispatcher without it being enabled at the same time.
>
> One thing I'll note about multi-conn is that it requires a variable in 
> connection.c to be set to the number of cpu's on the system where 
> slapd will be run.  I think this should instead be changed to a 
> parameter in slapd.conf (slapd-cpus ??) so one doesn't have to have 
> fixed slapd's for given systems.  That same parameter could be used 
> for giving guidelines to slapadd/slapdindex as well, and the 
> tool-threads parameter could be replaced by the new one.
The multi-conn code definitely needs more attention, it breaks the Win32 
build in its current state.

Along those lines,  in the normal (non-Win32) case I don't see an actual 
need for the connections_mutex. Since we go directly from descriptor 
number to connection slot, there's really no shared resource to protect 
that isn't already protected by the conn->c_mutex.

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