Re: [PATCH] O6int for interactivity

Mike Galbraith
2003-07-18T15:36:34Z

At 06:46 AM 7/18/2003 -0700, Davide Libenzi wrote:
>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

Yeah, I noticed... it's a nasty little bugger.

>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

If I hadn't done the restart after 30 seconds thing, I knew it would take
ages. I wanted something to see contrast, not a life sentence ;-)

>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.

(Oh, I agree that the problem is nasty. I like fair scheduling a lot...
when _I'm_ not the one starving things to death;)

-Mike