Re: [RFA] Try2: Ignore breakpoints when reading memory.

Joel Brobecker
2008-02-25T19:39:49Z

> On Sun, 2008-02-24 at 17:50 +0300, Vladimir Prus wrote:
> > This patch is the immediate prerequisite for the
> > patch that makes breakpoints always inserted.
>
> Hmmm? Did I miss this discussion?

I think this is part of:

Non-stop multi-threaded debugging
http://sourceware.org/ml/gdb/2007-11/msg00198.html

You need to leave the breakpoints inserted if you are to allow
the other threads to continue running.

> I'm not sure leaving breakpoints always inserted is a good idea.
> If gdb becomes unexpectedly disconnected from the target/child,
> these breakpoints become an instant problem, and even if you
> can manage to re-connect, it's not a given that you can then
> remove them.

That's indeed a risk, but I believe that this behavior would not
be the default.

Incidentally, I think this could also be very useful in the context
of very very slow debugging lines. We very recently had a customer
who asked about the reason for removing the breakpoints at every stop,
because apparently with his JTAG probe, inserting 30 breakpoints and
then removing them takes a long time (~10secs). We have also verified
that writing memory takes equally long. The customer is still waiting
to hear from the manufacturer about this lack of performance which seems
a bit suspicious, but having the option of keeping the breakpoints
inserted in this case would be a nice work-around.

--
Joel