Re: `nice' issues

Chris Schleicher (chrissch@cs.uoregon.edu)
Fri, 23 May 1997 11:24:17 -0700

>at CMU. On IRIX machines, we currently run deschall like
>this:
>
> npri -h 150 deschall keymaster.verser.frii.com
>
>My understanding is that this puts gives deschall a fixed
>priority level of 150, which means that it will *never*
>use CPU when a normal interactive process needs the CPU.

Not so. (at least on IRIX 6.2; I've yet to try it on 6.3, 6.4). I've
gone even further and tried

npri -n39 -h254 deschall ...

which should be _really_ conservative. Unfortunately, deschall
still keeps significant (read 30% or more) chunks of the CPU even when
other user processes should be getting 100%. Ugh.

>At niceness-level 19, if deschall is competing for CPU with
>a single normal-priority process, most Unix variants will
>give about 5% of the CPU to deschall and 95% to the
>normal-priority process. If there is more than one other
>cpu-bound process, deschall will get even less.

Now if only this were the case on IRIX. :-) Our Solaris boxes
are happily running 24/7 at nice -19 (/usr/bin/nice, that is).

Anyone out there know how to get truly weightless (or at least something
closer to the 95/5 split) processes on IRIX?

Thanks,

--Chris

--
     Chris Schleicher                      Office:  541/346-3998
     Univ of Oregon CIS GTF                email: chrissch@cs.uoregon.edu
                URL: http://www.cs.uoregon.edu/~chrissch/