RE: [FYI] tutorial for process record and reverse debugging

Marc Khouzam
2009-10-21T14:55:45Z

> -----Original Message-----
> From: gdb-owner@sourceware.org
> [mailto:gdb-owner@sourceware.org] On Behalf Of Michael Snyder
> Sent: Tuesday, October 20, 2009 4:06 PM
> To: Marc Khouzam
> Cc: 'Hui Zhu'; 'gdb@sourceware.org'
> Subject: Re: [FYI] tutorial for process record and reverse debugging
>
> [...]
> > Now, let me describe the case I am imagining.
> > It is as simple as it gets.
> > The user simply enables the 'reverse debugging' feature.
> > After that, the user should not need to pay attention to
> > record logs and such. What they should see is that they
> > can go forward or backwards as if everything was true 'execution'.
> > We don't need to differentiate between 'execution' and 'replay'.
> >
> > For example, when changing memory, the user doesn't need to know
> > that we are moving away from replay into a new execution. All
> > they see is that the program moves forward with the new memory
> > value.
> >
> > And that is why, in this scenario, I thought it seemed
> > unintuitive to stop execution when
> > arriving at the end of the replay log; instead, the user
> > pressed 'continue' and the 'execution' should continue until
> > a breakpoint or the end of the program, as if a true execution.
> >
> > The only limitation to this, is that we cannot go backwards
> > past the start of the recording. But I think this can be easily
> > understood by the user.
> >
> > I don't think this scenario is good for everyone, but I think
> > for average users, it makes reverse debugging very fluid.
>
> I think that's a great scenario -- just not the only scenario.
> We could call that Marc-mode, for devel purposes. ;-)

Just so it doesn't go to my head, how about "auto-mode"
as in "transitions from replay to record are done automatically"
(and without querying the user).

> How would you suggest we might turn on Marc-mode with a
> single command?

Maybe we can introduce a user setting such as
"record mode <auto|someothermode>"

> Or do you imagine it being the default?

Greg's follow-up email made me re-think a bit how intuitive
auto-mode would be. I'll reply to his email with my comments.

Marc