Re: Using reverse execution

[Michael Snyder <michsnyd at cisco dot com>]

>>> As a comparison, for tracepoints we came up with various
>>> scenarios for how they would be amazingly useful and powerful,
>>> and yet after nearly a decade they remain a curiosity in GDB.
>>
>> IMHO, tracepoints remain a curiosity because they were never
>> implemented on a large enough number of platforms.  Lack of
>> native support, in particular, is the main reason for its non-use.
>
> But don't you think it's telling that not one single person
> was willing to go to the trouble of implementing it on more
> platforms?  When breakpoints don't work on a platform, users
> don't say "oh well, we'll just have to do without". Apparently
> tracepoints are just not a must-have.

Eli remarked that the usefulness of reverse execution was a
no-brainer for him, and it's obviously a no-brainer for you
and me and a number of other GDB maintainers.

And yet -- I have a target audience of engineers to whom
I've been trying to "sell" reverse execution -- and I have
a working implementation that I can demo, live, and a real-life
bug that I can show to be easy to debug with reverse execution,
and pretty damn hard otherwise.  And the majority of them will
go "wow", but they aren't jumping up and down demanding access
to this cool facility.

I think this is a familiar concept to us, but an unfamiliar
one for many users, and they may have to get their hands on
it and actually use it and play with it before they start to
get a feel for its true power.

The same may have been true for tracepoints.  There were some
people who went "wow", and even a few who took a stab at doing
a target implementation -- but few people ever actually got to
get their hands on it and play with it.  Even a live demo is
not always as convincing as that.