Re: Updated ec-burst.diff patch

"M. Warner Losh" wrote:
> In message: <20030701164231.M88547_at_root.org>
>             Nate Lawson <nate_at_root.org> writes:
> : On Wed, 2 Jul 2003, Florian Smeets wrote:
> : > I set hw.acpi.ec.burst_mode=0 in loader.conf but when i was trying to
> : > chek if it was set to 0 with sysctl hw.acpi.ec.burst_mode i got :
> : >
> : > flo_at_lappi [~] 15 #sysctl hw.acpi.ec.burst_mode
> : > sysctl: unknown oid 'hw.acpi.ec.burst_mode'
> :
> : It's a tunable, not a sysctl.  So you can only set it in loader.conf.  Are
> : there any messages when you boot with that in your loader.conf?  Would you
> : please post a separate dmesg for that case?
> 
> I personally think that all tunable should be read-only (or rw if
> possible) sysctls...

Tunables are just sysctl's that are accessible from the loader
namespace.

Mostly, they are used for things that have no effect after SYSINIT
has run, e.g. things like maxfiles, which limit the number of inpcb's
and tcpcb's, such that *no matter what* you set them to after boot
time, their effect is nothing -- or limited.

In the case that it's limited, rather than nothing, it should be
writeable.

Technically, I think that all SYSCTL's should be tunables -- in
other words, you should be able to set defaults via the loader for
things that are runtime tunable, if your defaults don't match the
compile-time values.

So I would go the exact opposite of the way you are apparently
suggesting.

-- Terry