Re: [PATCH] Fast tracepoints

[Stan Shebs <stanshebs at earthlink dot net>]

Tom Tromey wrote:
> > > > > > "Stan" == Stan Shebs <stan@codesourcery.com> writes:
> > > > > >             
>
> Stan> This patch adds "fast" tracepoints to GDB.
>
> Neat.
>
> Stan> Most of the interesting trickery is on the target side - but don't
> Stan> despair, Pedro has upcoming patches for a free version using gdbserver
> Stan> and a special library.
>
> I wonder whether this could somehow work with systemtap probe points.
>   
One of our other projects is to do "static tracepoints" that originate 
outside GDB, and one of the side effects of the upcoming disconnected 
tracing patch is that it introduces the idea of keeping the tracepoint 
definition in the target.  So it seems like a useful convergence to have 
a tool-independent notion of a probe/tracepoint that can be used in 
different contexts.
> It seems like it would be nicer for the user if the _at method returned
> a reason, so that it could be printed as "May not have a fast
> tracepoint: ... : reason".
>   
Yeah, I considered it.  It seemed like a localization mess to be 
constructing strings from strings, plus I find it distasteful to have 
the callee decide to allocate space in a way that compels the caller to 
think about what to do with it.  But as you observe, predicates doing 
printouts isn't great either.

Stan