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Re: Connection-handling threads

This may be a good case to work on tuning SLAPD_LISTEN.

By the way, how are you determining that the connect handler is taking
up the one cpu?

On 5/16/05, Howard Chu <hyc@symas.com> wrote:
> John Morrissey wrote:
> 
> >I run a cluster of several dual-processor OpenLDAP servers that are starting
> >to saturate one of their CPUs with OpenLDAP's connection-handling thread.
> >
> >The machines are healthy otherwise (memory consumption, disk I/O,
> >interrupts, etc.) so this single connection handling thread is the current
> >bottleneck in our installation. AFAICT, once this single thread starts
> >consuming an entire CPU, we've hit the wall even though the bulk of the
> >other CPU is idle.
> >
> >
> Yes, this is definitely a bottleneck. The IBM folks are currently
> experimenting with different approaches to improve the situation.
> 
> >I've considered running two slapd instances, one for each binding, but that
> >requires twice the disk space and twice the memory consumption. Ideally, I
> >would like to bind to two ports/interfaces and split connection handling
> >between two threads, one thread per bound socket. Our load balancers would
> >see each port/interface combination as a separate host and load balance
> >across the two, splitting the connection-handling CPU load fairly evenly
> >between the two CPUs.
> >
> >Is this idea feasible? Is there a better way of solving this, without
> >cutting the number of LDAP operations being performed or throwing more
> >hardware at it?
> >
> >
> Yes, it sounds like using a separate thread per listener would work for
> you. Obviously the code doesn't work this way at the moment, so you have
> a bit of hacking to do. I don't believe that the ultimate solution for
> slapd will use a dedicated thread per listener, since it requires a
> separate load balancer to make it viable, but certainly it would help
> your case.
> 
> --
>   -- Howard Chu
>   Chief Architect, Symas Corp.       Director, Highland Sun
>   http://www.symas.com               http://highlandsun.com/hyc
>   Symas: Premier OpenSource Development and Support
> 
>