sysctl

[Enji Cooper]

> On Jun 4, 2019, at 02:29, Michael Zhilin <mizhka at gmail.com> wrote:
> 
> Hi,
> 
> What do you mean under "5 hundred"?
> On 13-CURRENT with few modules incl ZFS, "sysctl -NTa" shows around 8
> hundred variables.

As Michael noted, there are a variable number of sysctls, generally ranging in the hundreds or thousands, for controlling or querying system components/properties.

The user can optionally specify a description for a sysctl, which can be queries via “sysctl -d” (see “man 8 sysctl for more details).

There should also be a description of the sysctl in the implementing subsystem manpage, e.g., “man 4 inet” briefly describes the IPv4 stack and some of its sysctl knobs. However, there are gaps, e.g., Linux compat hooks which convert sysfs entries to sysctls. 

Good luck :).
-Enji