Re: VERBOSE flags

["Dalessandro, Dennis" <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>]

On Tue, 2016-09-20 at 13:56 +0300, Leon Romanovsky wrote:
> > Yes we do have that, which illustrates that trace points can not do
> > everything. I had hoped to deprecate that at some point.
> > Regardless,
> > sometimes you want additional code to be added or to do something
> > slightly different. You can't do that with a tracepoint.
> 
> Can you elaborate more on this topic? Which limitations did you see
> in tracepoints?

Just making up an example. Say you have a hash table. You want to dump
the items. If you iterate over it and do a trace point, yeah the actual
trace point has little to no perf impact, but you still walk the
table. 

There are situations where you need to do more for debugging than just
printing a message. 

> In regards of other discussion in KS 2016, "tracepoints and ABI
> stability warranties" [1]. Are you strict with this tracepoints ABI?

Honestly we are not super strict about it, but do take care not to
break/remove something that could be useful. It will be interesting to
see what comes out of the discussion. Perhaps we do need to be more
strict about them going forward.

-Denny