Re: extent-patch and overview of what is supposed to follow

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Wed, Apr 06, 2011 at 12:43:16PM -0400, Thor Lancelot Simon wrote:
> On Wed, Apr 06, 2011 at 06:34:15PM +0200, Manuel Bouyer wrote:
> > 
> > The point it: I don't want probes to be temporarily. When you notice a
> > problem it's too late to start the probe.
> 
> How can you have both things you seem to want?  In your other message,
> you seemed concerned that (you thought) DTrace was turned on for all
> probes all the time, generating data.  But now it sounds like exactly what
> you want is a debug facility that is turned on all the time, generating
> data.

No, I meant that if we use dtrace as a remplacement for KMEMSTATS,
it will be running all the time because KMEMSTATS is running all
the time when compiled in.

> 
> In practice, it is entirely feasible to have a small set of DTrace
> probes always running.  Start them at boot time, let them run.  This
> is the kind of case where the ability to summarize data (counts,
> histograms, etc.) is so valuable, so you do not end up generating a
> textual data stream that is output all the time as the system runs.

Would someone provide a DTrace setup to do what KMEMSTATS is actually
doing, then ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--