Sowmini.Varadhan at Sun.COM writes:
> One of the features that makes ndd very popular is that it allows
> the setting of these debug/workaround knobs "on the fly", i.e., no reboot
> required (as in /etc/system), and the driver can actually re-adjust
> its state based on the setting requested (mdb cannot trigger state
> re-adjustment in the driver by itself).

Yep; understood.

> Providing a way to do this on-the-fly debug/workaround setting was
> one of the motivations for private properties. I agree that there is a
> danger of abuse here, and maybe we can think of ways to control
> the danger (by controlling documentation, perhaps?), but I see a benefit
> in having private props for the short term, at least.

It's exactly that abuse that I'm worried about.  One of the reasons
for doing Brussels is that driver parameters have historically been
the Old West for configuration.  How do we make sure that Brussels
itself doesn't become just a new dumping ground?

> Actually, I myself felt that bcopy/dma threshold, as well as
> some of the ipg properties that have been suggested as public property
> candidates, also fell in the "Advanced Usage" bucket..

Ick.  I'd put it in the class of things that, if we were producing
solid designs, would just never need to be touched at all.  There's a
line here between allowing configuration for special purposes
(disabling autonegotiation, perhaps) and asking our customers to do
our design work for us (by figuring out the "optimal" way to move
data).  This is one that I think walks over the line.

We need a better answer.

> > Would it be good for us to retain them somehow in early phase of Brussel, 
> > like by ways of keep it as "private" properties? For backward compatibility 
> > reason, some customers might rely on those private properties in their 
> > production env. Before we provide enough tuning in framework, they will 
> > lose nothing.
> 
> I like Raymond's proposal..

I'd rather see those things left behind whereever they are -- ndd,
driver.conf -- and left out of Brussels user interfaces, with bugs
filed to have them removed completely over time.

-- 
James Carlson, Solaris Networking              <james.d.carlson at sun.com>
Sun Microsystems / 1 Network Drive         71.232W   Vox +1 781 442 2084
MS UBUR02-212 / Burlington MA 01803-2757   42.496N   Fax +1 781 442 1677

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