Re: Adding facility for injection points (or probe points?) for more advanced tests

On Mon, Jan 22, 2024 at 10:08 AM Michael Paquier <michael@paquier.xyz> wrote:
>
> On Thu, Jan 18, 2024 at 10:56:09AM +0530, Ashutosh Bapat wrote:
> > There is some overlap between Dtrace functionality and this
> > functionality. But I see differences too. E.g. injection points offer
> > deeper integration whereas dtrace provides more information to the
> > probe like callstack and argument values etc. We need to assess
> > whether these functionality can co-exist and whether we need both of
> > them. If the answer to both of these questions is yes, it will be good
> > to add documentation explaining the differences and similarities and
> > also some guidance on when to use what.
>
> Perhaps, I'm not sure how much we want to do regarding that yet,
> injection points have no external dependencies and will work across
> all environments as long as dlsym() (or an equivalent) is able to
> work, while being cheaper because they don't spawn an external process
> to trace the call.

Yes. Both have their advantages and disadvantages. So I believe both
will stay but that means the guidance is necessary. We may want to see
reception and add the guidance later in the release cycle.

>
> > Other code changes look good. I think the documentation and comments
> > need some changes esp. considering the users point of view. Have
> > attached two patches (0003, and 0004) with those changes to be applied
> > on top of 0001 and 0002 respectively. Please review them. Might need
> > some wordsmithy and language correction. Attaching the whole patch set
> > to keep cibot happy.
>
> The CF bot was perhaps happy but your 0004 has forgotten to update the
> expected output.  There were also a few typos, some markups and edits
> required for 0002 but as a whole what you have suggested was an
> improvement.  Thanks.

Sorry for that. Glad that you found those suggestions acceptable.

--
Best Wishes,
Ashutosh Bapat