OpenBSD 6.4 only using 1 core

Stuart Henderson stu at
Wed Feb 20 16:58:58 UTC 2019

On 2019-02-19, G Douglas Davidson via Unbound-users <unbound-users at> wrote:
>>>>> 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.

That's expected, recent OpenBSD no longer schedules to SMT (hyperthreading)
"cpu"s by default, controlled by sysctl hw.smt. We don't trust SMT, plus
with the current state of MP on OpenBSD for many workloads it works out
faster to avoid them anyway.

> Appreciate the reply. With so-reuseport: no, things are chugging along
> nicely, although the load is not particularly evenly distributed.

That's expected.

> I don't believe OpenBSD supports the _LB stuff as of now.


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