link state changes take a "long" time to execute

[Jeff Roberson]

On Thu, 9 Jun 2005, Robert Watson wrote:

>
> I'm running with task queue instrumentation on my notebook, and generate
> warnings when task queues take more than 1/10th of a second to execute.
> Normally the warnings fire only during the boot when tasks start being
> scheduled by ACPI, but the ACPI task queue thread isn't yet being
> scheduled to run because the scheduler hasn't been kicked off yet.  I saw
> one this afternoon as follows:
>
> taskqueue_run: warning, queue time of 0.133978201 for context 0xc0687c90
>
> On my kernel, this function pointer resolves to:
>
> c0687c90 t do_link_state_change
>
> So it sounds like there's a substantial delay in the link change thread --
> probably because another task takes a long time to execute, maybe
> blocking or delaying the task thread and preventing another task from
> running.  On this box, I'm running with an idle if_xl, and an in-use
> if_wi, which probably went into the associated state about when the
> message was printed.  Kernel source date is June 3.

If you save a ktrdump right when that message is generated it'll be easy
to understand if other threads are interfering.

>
> Robert N M Watson
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