Re: [PATCH 0/9] CPU controller

From: Mike Galbraith
Date: Fri Apr 28 2006 - 02:59:22 EST


On Fri, 2006-04-28 at 14:48 +0900, MAEDA Naoaki wrote:
> Hi Mike,
>
> On Fri, 28 Apr 2006 07:25:35 +0200
> Mike Galbraith <efault@xxxxxx> wrote:
>
> > On Fri, 2006-04-28 at 10:37 +0900, MAEDA Naoaki wrote:
> > > Andrew,
> > >
> > > This patchset adds a CPU resource controller on top of Resource Groups.
> > > The CPU resource controller manages CPU resources by scaling timeslice
> > > allocated for each task without changing the algorithm of the O(1)
> > > scheduler.
> > >
> > > Please consider these for inclusion in -mm tree.
> >
> > This patch set professes to be a resource controller, yet 100% of high
> > priority tasks are uncontrolled. Distribution of CPU among high
> > priority tasks isn't important, but distribution of what they leave
> > behind is?
>
> Do you mean niced tasks are uncontrolled by the controller?
> TASK_INTERACTIVEs are left untouched intentionally, but niced tasks
> are also controlled.

Until they attain interactive status. Note that attaining this status
requires only one sleep, and once attained, it can be sustained. I
don't know what the current exact numbers are, but until recently, the
numbers were that once sleep_avg became full, a non-niced task could
sustain ~95% cpu indefinitely.

You simply cannot ignore interactive tasks. At the very least, you have
to disallow requeue if the resource limit has been exceeded, otherwise,
this patch set is non-functional.

-Mike

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