Re: slapd responds very slowly when cpu has 100% usage (but actually low load)

[Howard Chu <hyc@symas.com>]

Antonis Christofides wrote:
> (My original message, which presents the problem, is at the bottom.)
>
> Thank you for your responses, here is some more information:
>
> > You didn't mention what version of slapd you're running.
>
> That's right, sorry.  I'm running Debian-packaged slapd 2.2.23-8,
> using bdb 4.2.52-18 (everything on my system is the Debian sarge's
> packages, except for the kernel, which is a recompiled Ubuntu 6.06
> kernel, 2.6.12 SMP).

You need to upgrade to OpenLDAP 2.3. There were a lot of gratuitous 
sched_yield() calls in OpenLDAP 2.2 that were removed in 2.3. These 
sched_yield() calls behave poorly with the scheduler in the Linux 2.6 
kernel.

--
  -- 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/