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Message-ID: <3e8340490803310825r407f792fv9158c0a9ee7cda93@mail.gmail.com>
Date: Mon, 31 Mar 2008 11:25:32 -0400
From: "Bryan Donlan" <bdonlan@gmail.com>
To: "Eric Descourtis" <desc0068@algonquincollege.com>
Subject: Re: Limiting CPU usage for processes in linux 2.6.18.8
Cc: linux-kernel@vger.kernel.org, eric.des.courtis@gmail.com
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On Sun, Mar 30, 2008 at 9:37 PM, Eric Descourtis
<desc0068@algonquincollege.com> wrote:
> Hello,
>
>  I would like to implement a patch to the scheduler that limits the CPU usage of individual
>  processes to a percentage in Linux 2.6.18.8 (Can't be any other version).
>  I would just like some feedback on the following questions:
>
>  1. How can I ensure that limited processes get their CPU time percentage allocation?
>  2. Are there mechanisms in place that would simplify this process?
>
>  I have been hitting my head against the wall for a long time now, any help would be appreciated.

The scheduler isn't really designed to force programs to idle when
there's nothing else to run - that would be a waste :)

If the reason you're on 2.6.18.8 is for Xen, you might want to try
using a recent kernel with paravirt ops, and use the CFS fair group
(or user) scheduler to set cpu shares. See
Documentation/sched-design-CFS.txt . If you really want to eat up a
certain portion of CPU time doing nothing, you could create a program
to busy-loop to starve the others and set CPU shares appropriately,
though I don't really see the point in that.
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