KTR_SPAREx

[Alexander Leidinger]

On Tue, 5 Jun 2012 21:14:02 +0100 Attilio Rao <attilio at freebsd.org>
wrote:

> 2012/6/5 Adrian Chadd <adrian at freebsd.org>:
> > Hi,
> >
> > I'm very tempted to make if_ath use KTR_DEV, but then have an extra
> > ath sysctl which does something like:
> >
> > if (sc->sc_ktr_enable)
> >    KTR();
> 
> But the actual problem is that your output will be overwhelmed by the
> clutter of all the other KTR_DEV consumers.
> 
> We very much need an much higher granularity on KTR classes and
> possibly a way to use it on-the-fly for kernel development and I think
> what I suggested earlier makes sense.

How much of the uncovered uses of KTR really need KTR (instead of
dtrace)? How many of them are time critical enough that dtrace is not
fast enough? How many of them need to run very early so that not enough
kernel infrastructure is available to run dtrace (can we run dtrace
scripts very early during boot (when enough kernel infrastructure is
available, before anything in userland starts) like in Solaris)?

Bye,
Alexander.

-- 
http://www.Leidinger.net    Alexander @ Leidinger.net: PGP ID = B0063FE7
http://www.FreeBSD.org       netchild @ FreeBSD.org  : PGP ID = 72077137