Re: Linux 2.6.0-test6

Nick Piggin
2003-09-30T01:12:15Z

bill davidsen wrote:

>In article <3F77BB2C.7030402@cyberone.com.au>,
>Nick Piggin <piggin@cyberone.com.au> wrote:
>
>| AFAIK, Con's scheduler doesn't change the nice implementation at all.
>| Possibly some of his changes amplify its problems, or, more likely they
>| remove most other scheduler problems leaving this one noticable.
>|
>| If X is running at -20, and xmms at +19, xmms is supposed to still get
>| 5% of the CPU. Should be enough to run fine. Unfortunately this is
>| achieved by giving X very large timeslices, so xmms's scheduling latency
>| becomes large. The interactivity bonuses don't help, either.
>
>Clearly the "some is good, more is better" approach doesn't provide
>stable balance between sound and cpu hogs. It isn't a question of "how
>much" cpu, just "when"which works or not.
>
>This is sort of like the deadline scheduler in that it trades of
>throughput for avoiding jackpot cases. I think that's desired behaviour
>in a CPU schedular too, at least if used by humans.
>

I'm not sure what you mean. There is nothing good to say about Ingo's
nice mechanism though (sorry Ingo, its otherwise a very nice
scheduler!).

In my scheduler, nice -20 processes get small timeslices so scheduling
latency stays low or even gets lower, while nice +19 ones get large
timeslices for lower context switches and better cache efficiency. As
you would like.