[dtrace-discuss] [networking-discuss] Re: DTrace Network Providers, take 2

[Darren.Reed at Sun.COM]

Bryan Cantrill wrote:

> ...
>
>>While we may well hide behind the veil of "sdt probes are private",
>>in the great big world of open source, this is just silly.  Everyone
>>can see they're there and how they can or cannot use them.  If someone
>>who isn't a developer wanted to use dtrace to collect inbound packet
>>statistics using dtrace and found sdt:::ip4-physical-in-start as being
>>useful, who are we to say they can't if it serves their needs?
>>    
>>
>
>Yes, that's _exactly_ why we added a programmatic notion of stability.
>So yes, you should knock yourself out adding Private SDT providers -- they
>don't even require an ARC case.  And if they serve a customer's needs,
>great -- because you will have declared them to be Private, a customer
>that cares about the stability of their D scripts will know that their
>script can be broken by any twitch of the operating system.
>
>That said, there is great value in adding stable (or in this case, Evolving)
>SDT providers -- they allow customers to build those stable scripts that
>have been so useful in things like the DTraceToolkit.
>
>So one can envision a spectrum of usage of DTrace, with Solaris developers
>on one end and end-users on the other:  FBT provides value primarily at the
>developer end, Stable/Evolving SDT providers provide value primarily at
>the end-user end, and Private SDT providers fall in between.  So these
>are not mutually exclusive -- it's a question of the audience, and the
>audience for Brendan's work is very much the end-user.
>  
>

Adam's email suggest that SDT probes are only ever going to be
private but you're suggesting otherwise and those that Brendan
is working on aren't SDT, if I recall correctly.  Who's right here?

While I don't actually envisage wanting to promote an SDT probe,
at this point, to anything above private, I'd just like to know if there
is some subtlety to the difference between what you've said above
and what Adam was saying that I'm missing.

Darren