LOCK_PROFILING in -stable

[Alfred Perlstein]

* Robert Watson <rwatson at FreeBSD.org> [071020 10:21] wrote:
> 
> On Sat, 20 Oct 2007, Kris Kennaway wrote:
> 
> >Alfred Perlstein wrote:
> >>Hey guys, I have LOCK_PROFILING done for a product based on FreeBSD-6, 
> >>this means I can relatively easily backport LOCK_PROFILING from FreeBSD-7 
> >>to FreeBSD-6.
> >>
> >>Do we want this?
> >>
> >>I'd like to do it if people want it.
> >
> >I think it should be done, performance is a lot better than the old 6.x 
> >version and it also adds another very useful performance metric (time 
> >spent waiting for the lock).  The only concern is that it doesn't break 
> >ABI support when not compiled in, but I'm pretty sure you've already told 
> >me this is OK. Thanks for looking at this.
> 
> This is my feeling also -- I would consider ABI breakage a show stopper for 
> 6.x, but feel otherwise that the new code is much more mature and capable 
> and would be quite beneficial to people building appliances and related 
> products on 6.x. You might check with Attilio about whether there are any 
> remaining outstanding issues that need to be resolved first, and make sure 
> to send a heads up out on stable@ and put a note in UPDATING that the 
> option and details have changed.

I still get confused as to the meaning of this...

It only breaks ABI when it's enabled.

I think that is OK, right?

-- 
- Alfred Perlstein