LOCK_PROFILING in -stable

[Kris Kennaway]

Alfred Perlstein wrote:
> * 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?
> 

Yes, that is fine.  Other existing debugging options also break ABI when 
enabled, so it's OK.

Kris