Re: Problems with wait queues

From: Nicolas Bougues (nbougues-listes@axialys.net)
Date: Wed Jun 26 2002 - 09:00:29 EST


On Wed, Jun 26, 2002 at 12:52:41PM +0200, Andries Brouwer wrote:
> On Wed, Jun 26, 2002 at 12:32:43PM +0200, Nicolas Bougues wrote:
>
> > Does anybody have any idea on what I may have done wrong, and why
> > would loadavg increase when vmstat show no activity ?
>
> loadavg does not report what you think it reports
>

As far as I understand, loadavg reports the average number of
processes in the TASK_RUNNING state.

What happens in my driver, I believe, is that :
- on timer interrupt, I do some stuff, and wake_up the waiting process
- then the loadavg is computed (seeing my waiting task as TASK_RUNNING)
- then the scheduler runs the task
- then the task goes immediatly back to sleep

>From this point of view, then my problem is just "cosmetic". Isn't
there a way to do things in a different order, so that I could still
get a meaningful(*) loadavg ?

(*): by meaningful, I mean representing the number of busy processes
at a random point in time.

--
Nicolas Bougues

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