freebsd stable - Dec 2017 - idprio(1) broken

Hi!

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.

Eugene Grosbein

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.