unexpected idprio 31 behavior on 9.2-BETA2 and 9.2-RC1

[Eric van Gyzen]

On 08/06/2013 14:23, J David wrote:
> On Tue, Aug 6, 2013 at 1:59 PM, Eric van Gyzen <eric at vangyzen.net> wrote:
>>> on an otherwise idle amd64 system with 4 CPUs.  The first command in the
>>> build.log file:
>>>
>>>     rm -rf /usr/obj/home/freebsd/tmp
>>>
>>> took over three minutes.  It should have taken about three /seconds/.
>>>
>>> "uptime" reported a load average of around 1.00.
>>> "top" showed no threads (user or kernel) using CPU.
>>> "iostat" showed an average of less than 20 tps on ada0.
>>> "rm" was usually in the RUN state.
> We are looking at something similar.  Would you be able to try to
> reproduce it using a kernel with:
>
> nooptions	SCHED_ULE
> options		SCHED_4BSD
>
> to see if it makes a difference?  It seems to, but the problem is
> inconsistent enough that I can't be sure.

The 4BSD scheduler does //not// exhibit this problem.  I tested with the
latest releng/9.2 (r254054) and an otherwise GENERIC config.

Eric