OpenBSD 6.4 only using 1 core

Mon Feb 18 19:57:08 UTC 2019

OpenBSD 6.4 and the included Unbound 1.8.1.  Intel NUC with 2 real CPUS and 2 Virtual.  Some sysctl stuff:

	hw.ncpu=4
	hw.ncpufound=4
	hw.ncpuonline=2
	hw.smt=0

“top” shows four cpus with work distributed to only two of them.  “ps” and the statistics emitted by Unbound show only one CPU working.

ps output:

	87709 ??  Is      0:00.02 unbound -c /var/unbound/etc/unbound.conf
	86298 ??  S       1:49.24 unbound -c /var/unbound/etc/unbound.conf

unbound statistics (every hour):

> Feb 18 13:14:02 unbound1 unbound: [87709:0] info: server stats for thread 0: 0 queries, 0 answers from cache, 0 recursions, 0 prefetch, 0 rejected by ip ratelimiting
> Feb 18 13:14:02 unbound1 unbound: [87709:0] info: server stats for thread 0: requestlist max 0 avg 0 exceeded 0 jostled 0
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info: server stats for thread 1: 47870 queries, 18749 answers from cache, 29121 recursions, 0 prefetch, 0 rejected by ip ratelimiting
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info: server stats for thread 1: requestlist max 46 avg 5.96944 exceeded 0 jostled 0
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info: average recursion processing time 0.888912 sec
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info: histogram of recursion processing times
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info: [25%]=0.0276987 median[50%]=0.0609112 [75%]=0.128225
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info: lower(secs) upper(secs) recursions
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.000000    0.000001 2779
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.000008    0.000016 7
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.000064    0.000128 1
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.000128    0.000256 5
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.000256    0.000512 25
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.000512    0.001024 197
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.001024    0.002048 69
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.002048    0.004096 52
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.004096    0.008192 103
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.008192    0.016384 222
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.016384    0.032768 5530
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.032768    0.065536 6483
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.065536    0.131072 6653
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.131072    0.262144 4023
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.262144    0.524288 1786
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    0.524288    1.000000 604
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    1.000000    2.000000 224
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    2.000000    4.000000 72
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    4.000000    8.000000 64
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:    8.000000   16.000000 53
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:   16.000000   32.000000 52
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:   32.000000   64.000000 49
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:   64.000000  128.000000 4
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:  128.000000  256.000000 30
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:  256.000000  512.000000 23
> Feb 18 14:14:02 unbound1 unbound: [86298:1] info:  512.000000 1024.000000 6
> Feb 18 14:14:02 unbound1 unbound: [87709:0] info: server stats for thread 0: 0 queries, 0 answers from cache, 0 recursions, 0 prefetch, 0 rejected by ip ratelimiting
> Feb 18 14:14:02 unbound1 unbound: [87709:0] info: server stats for thread 0: requestlist max 0 avg 0 exceeded 0 jostled 0

unbound.conf:

>         num-threads: 2

No other tweaks make to unbound.conf.  Version is as distributed under OpenBSD 6.4.  Unbound works find under OpenBSD 6.2 on a cpu with 2 real cores and no virtual.

I’m thinking that this issue may have something to do with the way OpenBSD is reporting available CPUs.  I’m going to turn hyperthreading off at the BIOS level at some point (when I can.)  I am wondering if anyone has any experience with this.  Where “this” is OpenBSD and Unbound with hw.smt=0 and Unbound apparently not using more than one thread.

Thanks for any feedback!

—doug

--
G Douglas Davidson
douglas at readyforgo.com