Re: [patch] new scheduler

Ingo Molnar (mingo@chiara.csoma.elte.hu)
Mon, 10 May 1999 12:37:42 +0200 (CEST)


On Mon, 10 May 1999, Pavel Machek wrote:

> This easily doable on linux, too. Even on current scheduler (because
> it has problems with accounting...):

> PS: It would be nice to modify kernel to be _pessimistic_ about
> idle. Right now it is so optimistic that you can run boy bad and see
> 0% cpu utilization when it is in fact 80%. It would be much better to
> report worse values than to report better values.

i cant seem to be able to reproduce the 'bad' behavior on 2.2.8:

[mingo@moon lo]$ time ./badguy
I'm a good boy.
..........4.66 user 0.41 system 0:05.07 elapsed 99%CPU
[mingo@moon lo]$ time ./badguy bad
I'm a *BAD* boy! And bad boys know that jiffie is 20msec
..........4.66 user 0.43 system 0:05.12 elapsed 99%CPU
[mingo@moon lo]$

(i've tried it both on SMP and UP boxes) In both cases the kernel says
we've spent almost 100% as user-time. (are you sure 2.2 still has this
problem? I saw your(?) timer tick accounting fix half a year ago, and i
thought it went into the kernel, but i could be wrong.)

-- mingo

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