reading kernel tunables from userland ?

[John Baldwin]

On Wednesday 23 April 2008 11:39:18 am Dan Nelson wrote:
> In the last episode (Apr 23), Luigi Rizzo said:
> > On Wed, Apr 23, 2008 at 02:14:02PM +0400, pluknet wrote:
> > > 2008/4/23 Luigi Rizzo <rizzo at iet.unipi.it>:
> > > > sorry for the possibly naive question, but is there a way other
> > > >  than sysctl to read the value of kernel 'tunable' variables ?
> > > >
> > > >  E.g. in if_nfe.c i see
> > > >
> > > >  TUNABLE_INT("hw.nfe.msi_disable", &msi_disable);
> > > >  TUNABLE_INT("hw.nfe.msix_disable", &msix_disable);
> > > >  TUNABLE_INT("hw.nfe.jumbo_disable", &jumbo_disable);
> > > >
> > > >  but sysctl is reporting none of them.
> > > >
> > > >  I seem to remember that there was a separate command to access
> > > >  kernel tunables, but cannot remember which one, and neither 'man
> > > >  -k tunable' nor a google search return any useful answer...
> > >
> > > Perhaps are you about kenv ?
> >
> > yes, thanks...
>
> Is there any reason to have TUNABLE_* macros anymore?  A SYSCTL_* macro
> with the CTLFLAG_TUN flag does the same thing and also provides sysctl
> access.

Err, no it doesn't.  The flag exists but it is meaningless.

-- 
John Baldwin