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Subject: Re: O(1) scheduler & interactivity improvements
From: Daniel Gryniewicz <dang@fprintf.net>
To: Felipe Alfaro Solana <felipe_alfaro@linuxmail.org>
Cc: Helge Hafting <helgehaf@aitel.hist.no>,
       LKML <linux-kernel@vger.kernel.org>
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On Mon, 2003-06-23 at 06:18, Felipe Alfaro Solana wrote:

> If a process has received user
> input in the past, ir's pretty probable that the process is an
> interactive one.

<snip>

> So then, why I can easily starve the X11 server (which should be marked
> interactive), Evolution or OpenOffice simply by running "while true; do
> a=2; done". Why don't they get an increased priority boost to stop the
> from behaving so jerky?

You're own metric will kill you here.  You're while true; loop is
running in the shell, which is interactive (it has accepted user in put
in the past) and can therefore easily starve anything else.  You need a
an easy way to make an interactive process non-interactive, and that's
what these threads are all about, making interactive threads
non-interactive (and the other way around) in a fashion that maximises
the user experience.  A history of user input is not necessarily a good
metric, as many non-interactive CPU hogs start out life as interactive
threads (like your loop above).
-- 
Daniel Gryniewicz <dang@fprintf.net>

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