Re: [PATCH] O6int for interactivity

From: Davide Libenzi <davidel@xmailserver.org>
To: Mike Galbraith <efault@gmx.de>
Cc: Con Kolivas <kernel@kolivas.org>,
	linux kernel mailing list <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@osdl.org>,
	Felipe Alfaro Solana <felipe_alfaro@linuxmail.org>,
	Zwane Mwaikambo <zwane@arm.linux.org.uk>
Subject: Re: [PATCH] O6int for interactivity
Date: Fri, 18 Jul 2003 06:46:53 -0700 (PDT)	[thread overview]
Message-ID: <Pine.LNX.4.55.0307180630450.5077@bigblue.dev.mcafeelabs.com> (raw)
In-Reply-To: <5.2.1.1.2.20030718071656.01af84d0@pop.gmx.net>

On Fri, 18 Jul 2003, Mike Galbraith wrote:

> At 03:12 PM 7/16/2003 -0700, Davide Libenzi wrote:
>
> >http://www.xmailserver.org/linux-patches/irman2.c
> >
> >and run it with different -n (number of tasks) and -b (CPU burn ms time).
> >At the same time try to build a kernel for example. Then you will realize
> >that interactivity is not the bigger problem that the scheduler has right
> >now.
>
> I added an irman2 load to contest.  Con's changes 06+06.1 stomped it flat
> [1].  irman2 is modified to run for 30s at a time, but with default parameters.

In my case I cannot even estimate the time. It takes 8:33 ususally to do a
bzImage, and after 15 minutes I ctrl-c with only two lines printed in the
console. If you consider the ratio between the total number of lines that
a kernel build spits out, this couls have taken hours. Also, you might
want also to try a low number of processes with a short burn, like the new
patch seems to do to better hit mm players. Something like:

irman2 -n 10 -b 40

Guys, I'm saying this not because I do not appreciate the time Con is
spending on it. I just hate to see time spent in the wrong priorities.
Whatever super privileged sleep->burn pattern you code, it can be
exploited w/out a global throttle for the CPU time assigned to interactive
and non interactive tasks. This is Unix guys and it is used in multi-user
environments, we cannot ship with a flaw like this.

- Davide