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

[Eric van Gyzen]

On 08/08/2013 09:19, Eric van Gyzen wrote:
> 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.

To be thorough, I built a GENERIC kernel at the same rev, and it still
exhibits the problem.

Eric