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SubjectRe: [PATCH] O13int for interactivity
Quoting Nick Piggin <piggin@cyberone.com.au>:

> Con Kolivas wrote:
>
> >Quoting Nick Piggin <piggin@cyberone.com.au>:
> >
> >
> >>
> >>Con Kolivas wrote:
> >>
> >>
> >>>On Tue, 5 Aug 2003 12:21, Nick Piggin wrote:
> >>>
> >>>
> >>>>No, this still special-cases the uninterruptible sleep. Why is this
> >>>>needed? What is being worked around? There is probably a way to
> >>>>attack the cause of the problem.
> >>>>
> >>>>
> >>>Footnote: I was thinking of using this to also _elevate_ the dynamic
> >>>
> >>priority
> >>
> >>>of tasks waking from interruptible sleep as well which may help
> throughput.
> >>>
> >>>
> >>Con, an uninterruptible sleep is one which is not be woken by a signal,
> >>an interruptible sleep is one which is. There is no other connotation.
> >>What happens when read/write syscalls are changed to be interruptible?
> >>I'm not saying this will happen... but come to think of it, NFS probably
> >>has interruptible read/write.
> >>
> >>In short: make the same policy for an interruptible and an uninterruptible
> >>sleep.
> >>
> >
> >That's the policy that has always existed...
> >
> >Interesting that I have only seen the desired effect and haven't noticed any
>
> >side effect from this change so far. I'll keep experimenting as much as
> >possible (as if I wasn't going to) and see what the testers find as well.
> >
>
> Oh, I'm not saying that your change is outright wrong, on the contrary I'd
> say you have a better feel for what is needed than I do, but if you are
> finding
> that the uninterruptible sleep case needs some tweaking then the same tweak
> should be applied to all sleep cases. If there really is a difference,
> then its
> just a fluke that the sleep paths in question use the type of sleep you are
> testing for, and nothing more profound than that.

Ah I see. It was from my observations of the behaviour of tasks in D that
found it was the period spent in D that was leading to unfairness. The same
tweak can't be applied to the rest of the sleeps because that inactivates
everything. So it is a fluke that the thing I'm trying to penalise is what
tasks in uninterruptible sleep do, but it is by backward observation of D
tasks, not random chance.

Con
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