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

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.