On Sat, Apr 19, 2025 at 06:24:56PM -0400, Joel Fernandes wrote:
> Hi Paul,
>
> On 4/18/2025 6:45 PM, Paul E. McKenney wrote:
> >>>>> Suppose we fired up a guest OS and captured the console output. Is
> >>>>> there
> >>>>> a way to make that guest OS shut down automatically at the end of the
> >>>>> test and to extract the test results?
> >>>> Ah, sorry, I thought you were already doing something like that, i.e.
> >>>> that perhaps you could reuse some kernel build you already had and
> >>>> avoiding a full rebuild/mrproper. The KUnit Python script uses QEMU
> >>>> and parses the results; e.g. you could look for the results lines
> >>>> like:
> >>>>
> >>>> # Totals: pass:133 fail:0 skip:0 total:133
> >>>> ok 2 rust_doctests_kernel
> >>>>
> >>> Alternatively, I could clone a copy of the current archive into a
> >>> temporary directory, "make mrproper" there, run kunit normally, then
> >>> clean up the temporary directory. Extra storage, but quite a bit
> >>> more robust and user-friendly.
> >>>
> >> Just to be on the same page, is the concern about the
> >> slowness of mrproper or that it kills the kernel build
> >> artifacts requiring a clean build?
> >
> > It blows away things like tags and cscope databases. Me, I have my
> > cscope databases elsewhere, but lots of people build them for their
> > live git repos. And they are (quite understandably) unhappy when their
> > source-code browsing tools are blown away by some random test doing an
> > unsuspected "make mrproper". 😉
>
> Cool. One thing is, running other test modes in torture.sh also reconfigures
> the
> kernel and potentially recompiles the entire kernel as a result. So if someone
> is already having their own kernel build, running torture.sh already may cause
> them to have to do a full rebuild, AFAICS. But yes, and to your point, the
> cscope DB and stuff may get blown away for additional disruption.
>
> >
> >> What kind of improvement are we looking for and why would
> >> this patch in its current form not work?
> > For the near term, I am OK with its current form because it is
> > non-default. Longer term, though, we need it to be tested by default,
> > and that means making it avoid undoing people's work. My short-term
> > approach is to enable this test on my employer's test systems, which
> > have Rust set up correctly, and skip it on my laptop, which has a strange
> > FrankenRust due to my early playing around with that language.
> >
> Or we teach kunit.py to not require a mrproper? :-) I wonder why it needs to
> do
> that. I may run into that too considering my other kernel project requires me
> to
> mess around with rust.
They might have a good reason for that "make mrproper", but it does
sound like a good avenue to investigate. Otherwise, as noted earlier, my
thought is to clone the repo into a temp directory, run "make mrproper"
there, continue being a non-special user of kunit, and avoid messing up
people's databases and tags.
Thanx, Paul
