Re: how to set priority for idle process ?

Charlie Ross (s253343@gettysburg.edu)
Sat, 12 Apr 1997 03:01:30 -0400 (EDT)


On Sat, 12 Apr 1997 sphilp@alliance.net wrote:

> and I'd like that the higher priority get *every* CPU time needed and
> they shouldn't need to compete with lower priorities at all (some kind of
> fixed priority scheduling).
>
> running 3 jobs with nice 0, 10 and 19 give the following distribution
> of CPU time:
>
> PID USER PRI NI SIZE RES SHRD STAT %CPU %MEM TIME COMMAND
> 480 root 17 0 816 56 28 R 61.6 0.1 0:37 idle
> 479 root 18 10 816 56 28 R N 31.9 0.1 0:19 idle
> 478 root 20 19 816 56 28 R N 5.0 0.1 0:03 idle
>
> so the interactive job looses ~40% cpu time due to background jobs.
> only running background and idle jon (nice 10 and 19) gives
>
> PID USER PRI NI SIZE RES SHRD STAT %CPU %MEM TIME COMMAND
> 483 root 18 10 816 56 28 R N 85.9 0.1 0:52 idle
> 482 root 20 19 816 56 28 R N 12.5 0.1 0:08 idle
>
> so the idle task still uses 12% CPU while it shouldn't as there are
> more important jobs around...

you can nice with negative values up to -20... from what I understand, a
process at -20 wont swap, or relinquish any cpu time unless its fighting
with another -20 process...

coments? I'm wearing my asbestos underwear...