Re: [ckrm-tech] Re: [PATCH 1/3] CPUMETER: add cpumeter framework tothe CPUSETS

From: Simon Derr
Date: Fri Sep 30 2005 - 04:40:08 EST




On Thu, 29 Sep 2005, KUROSAWA Takahiro wrote:

> > Oh I think not. My primary motivation in pushing on this point
> > of the design was to allow CPUSET 2a and 2b to have a smaller
> > cpumask than CPUSET 1a. This is used for example to allow a job
> > that is running in 1a to setup two child cpusets, 2a and 2b,
> > to run two subtasks that are constrained to smaller portions of
> > the CPUs allowed to the job in 1a.
>
> Maybe I still misunderstand your idea.
> The guarantee assigned to CPUSET 1a might not be satisfied if
> tasks are attached to CPUSET 2a only and no tasks are attached to
> CPUSET 1a nor CPUSET 2b. Does your idea leave as it is because
> the user sets up CPUSETs like that?

Hi Takahiro-san

It seems to me that this "guarantee" can only be guaranteed if the owner
of cpuset 1a:
-runs enough tasks to use all the cpus of cpuset 1a
-does not tamper with the scheduler decisions by creating other cpusets
inside cpuset 1a, or by using sched_setaffinity().

Outside of this, he accepts to get less cpu than "guaranteed".
Sounds acceptable to me.

Simon.

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