using tracepoints function with both host and target on same computer
Daniel Jacobowitz
drow@mvista.com
Wed Aug 7 08:01:00 GMT 2002
On Wed, Aug 07, 2002 at 09:51:53AM -0500, William A. Gatliff wrote:
> Eli:
>
>
> > IMHO, tracepoints should really become part of GDB itself, even for
> > native debugging. That would allow us to debug programs where timing is
> > critical, such as real-time software, Emacs display engine, etc. I miss
> > that feature a lot.
>
> Wouldn't some kind of stub be present in these situations anyway? So
> it'd still be an implementation concern for the stub...
>
> In fact, I don't see how you could do tracepoints effectively in
> anything resembling real time without stub assistance.
You don't do them in actual realtime, but neither do you wait for all
of GDB to process the event; you receive the breakpoint, collect
tracepoint data, and immediately resume without touching GDB's event
loop. It's a little slower than an in-application stub because it has
to use ptrace to read memory/registers, but not substantially slower.
If you need better, you have to link a stub into the application. I
think we've been investigating a library for that, but I don't know
when/if it'll be available.
--
Daniel Jacobowitz Carnegie Mellon University
MontaVista Software Debian GNU/Linux Developer
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