I'm going to fix this permanently.
> The kern.bufcachepercent entry in sysctl(2) still claims the default
> value is 80, even though it was changed to 20 recently.
>
>
> Index: ./lib/libc/sys/sysctl.2
> ===================================================================
> RCS file: /cvs/src/lib/libc/sys/sysctl.2,v
> retrieving revision 1.23
> diff -u -p -r1.23 sysctl.2
> --- ./lib/libc/sys/sysctl.2 21 Apr 2019 16:02:45 -0000 1.23
> +++ ./lib/libc/sys/sysctl.2 5 May 2019 16:28:44 -0000
> @@ -535,7 +535,7 @@ structure is returned.
> This structure contains the time that the system was booted.
> .It Dv KERN_CACHEPCT Pq Va kern.bufcachepercent
> The maximum percentage of physical memory the buffer cache may use;
> -the default is 80%.
> +the default is 20%.
> .It Dv KERN_CCPU Pq Va kern.ccpu
> The scheduler exponential decay value.
> .It Dv KERN_CLOCKRATE Pq Va kern.clockrate
>
