On Fri, Mar 23, 2001, Robert Watson wrote:
>
> On Fri, 23 Mar 2001, Alexey V. Neyman wrote:
>
> > On Thu, 22 Mar 2001, Michael C . Wu wrote:
> >
> > >(Why is vfs.vmiodirenable=1 not enabled by default?)
> > By the way, is there any all-in-one-place description of sysctl tuneables?
> > Looking all the man pages and collecting notices about MIB variables seems
> > rather tiresome and, I think, pointless. I doubt if they are all
> > documented in man pages.
>
> sysctl(3) describes a number of the constant-named sysctl variables, and a
> number of sysctl's are described in the man pages associated with the
> features tweaked by the sysctl's. For example, the jail(8) man page
> describes the jail.* namespace. However, you're right that there are vast
> hoards of under-documented sysctl's. That said, probably only the
> "tweakable" (writable) sysctl's need to be documented in the general case,
> since many are used for the sole purpose of exporting kernel data for
> supported interfaces, whereas the sysctl's are subject to change. For
> example, a large number of read-only sysctl's were introduced to support
> the non-setgid-kmem operation of top, systat, and various other *stat's
> recently. Also, many sysctl's are "self-documenting", in that the
> declaration of the sysctl macros in-kernel include a description field. I
> don't think sysctl(8) currently knows how to read that field, but if you
> look at the SYSCTL definitions in the kernel source, they're probably a
> decent starting point. A magic script to extract the sysctl names, types,
> and descriptions might be useful..
A while back I started running through the undocumented sysctls and
documenting them. I didn't get through all of them, and the main reason
I stopped was because there wasn't a nifty way to extract the sysctls
short of writing a script to extract them from /usr/src.
Someone did point out that you could stuff the sysctl's into an elf
segment and only load it when needed, but I don't know much about elf.
If someone would like to do this, I'm sure a small group of us
(Asmodai? :-P) could walk the sysctl tree again and figure out what
the undocumented sysctls are. :-)
adrian
--
Adrian Chadd "Programming is like sex:
<[EMAIL PROTECTED]> One mistake and you have to support for
a lifetime." -- rec.humor.funny
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