Re: [ck] Re: [ANNOUNCE] RSDL completely fair starvation freeinteractive cpu scheduler

[jos poortvliet]

Op Monday 05 March 2007, schreef Willy Tarreau:
> On Mon, Mar 05, 2007 at 08:49:29AM +1100, Con Kolivas wrote:
> (...)
>
> > > That's just what it did, but when you "nice make -j4", things (gears)
> > > start to stutter.  Is that due to the staircase?
> >
> > gears isn't an interactive task. Apart from using it as a background load
> > to check for starvation because it loads up the cpu fully (which a gpu
> > intensive but otherwise simple app like this should _not_ do) graphics
> > card drivers and interrupts and so on, I wouldn't put much credence on
> > gears as anything else. However I suspect that gears will still get a
> > fair share of the cpu on RSDL which almost never happens on any other
> > scheduler.
>
> Con,
>
> I've now given it a try with HZ=250 on my dual-athlon. It works
> beautifully. I also quickly checked that playing mp3 doesn't skip during
> make -j4, and that gears runs fairly smoothly, since those are the
> references people often use.
>
> But with real work, it's excellent too. When I saturate my CPUs by
> injecting HTTP traffic on haproxy, the load is stable and the command line
> perfectly responsive, while in the past the load would oscillate and the
> command line sometimes stopped to respond for a few seconds.
>
> I've also launched my scheddos program (you may remember, the one we did a
> few experiments with). I could not cause any freeze at all. Plain 2.6.20
> had already improved a lot in this area, but above 4 processes/CPU,
> occasional short freezes did still occur. This time, even at 100 processes,
> the system was rather slow (of course!) but just as expected, and nothing
> more.
>
> I also tried the good old "dd if=/dev/zero bs=1|...|dd bs=1 of=/dev/null"
> and it did not cause any trouble.
>
> I will boot 2.6 slightly more often to test the code under various
> conditions, and I will recommend it to a few people I know who tend to
> switch back to 2.4 after one day full of 2.6 jerkiness.
>
> Overall, you have done a great job !
>
> I hope that more people will give it a try, first to help find possible
> remaining bugs, and to pronounce in favour of its inclusion in mainline.
>
> Cheers,
> Willy

Sounds nice... you might want to put this in the -ck wiki: ck.wikia.com/

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