Re: [PATCH 0/11] LTTng-core (basic tracing infrastructure) 0.5.108

[Ingo Molnar <mingo@elte.hu>]

* Tim Bird <tim.bird@am.sony.com> wrote:

> > that's not true, and this is the important thing that i believe you 
> > are missing. A dynamic tracepoint is _detached_ from the normal 
> > source code and thus is zero maintainance overhead. You dont have to 
> > maintain it during normal development - only if you need it. You 
> > dont see the dynamic tracepoints in the source code.
> 
> It's only zero maintenance overhead for you.  Someone has to maintain 
> it. The party line for years has been that in-tree maintenance is 
> easier than out-of-tree maintenance.

There's a third option, and that's the one i'm advocating: adding the 
tracepoint rules to the kernel, but in a _detached_ form from the actual 
source code.

yes, someone has to maintain it, but that will be a detached effort, on 
a low-frequency as-needed basis. It doesnt slow down or hinder 
high-frequency fast prototyping work, it does not impact the source code 
visually, and it does not make reading the code harder. Furthermore, 
while a single broken LTT tracepoint prevents the kernel from building 
at all, a single broken dynamic rule just wont be inserted into the 
kernel. All the other rules are still very much intact.

	Ingo