idprio(1) broken

Eugene Grosbein eugen at grosbein.net
Tue Dec 26 09:18:32 UTC 2017


On 26.12.2017 16:10, Eugene Grosbein wrote:

> Is idprio(1) broken in stable/11?
> 
> As root, start one bzip2 instance with idprio and one additional bzip2 intance per CPU core:
> 
> # idprio 5 bzip2 -9 </dev/zero >/dev/null &
> # n=$(sysctl -n kern.smp.cpus)
> # i=1; while [ $i -le $n ]; do bzip2 -9 </dev/zero >/dev/null & i=$(($i+1)); done
> # top
> 
> For dual core system, I see that idprio'd bzip2 takes all cycles of first core
> and two "normal" bzip2's share cycles of second core each taking ~50% of CPU time.
> 
> It is expected that idprio'd bzip2 get no CPU time at all and each of "normal" bzip2's
> get ~100% of single CPU core for such setup.

This works as expected for stable/10.



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