Re: [PATCH 2/2] perf build: Add Debian/Ubuntu python-is-python3

[Namhyung Kim <namhyung@kernel.org>]

Hello,

On Fri, Oct 17, 2025 at 06:39:04PM +0200, Geert Uytterhoeven wrote:
> Hi Leo,
> 
> On Fri, 17 Oct 2025 at 14:29, Leo Yan <leo.yan@arm.com> wrote:
> > On Thu, Oct 16, 2025 at 02:44:12PM +0200, Geert Uytterhoeven wrote:
> > > The build looks for "python" and "python-config", while modern
> > > distributions provide only "python3" and "python3-config" by default.
> > > Suggest installing "python-is-python3" and "python-dev-is-python3", as
> > > available on Debian 11 (bullseye) and Ubuntu 20.04 LTS (focal) and
> > > later.
> >
> > Seems to me, this change is not necessary. The Makefile [1] searches
> > python[2|3]/python[2|3]-cofig if un-versioned executables are not found.
> >
> > I confirmed that I can build successfully without installation
> > python-dev-is-python3 package.
> 
>     $ sudo apt remove python-dev-is-python3 python-is-python3
>     $ make tools/perf
> 
> Indeed, it still works. I am quite sure I had to install both, and
> even verified that uninstalling them again broke the build again before
> creating my patch.
> 
> /me dives deeper.
> 
> Aha, I found it.  After uninstalling python3-dev, I got into the same
> state as yesterday:
> 
>     $ make tools/perf
>     [...]
>     Makefile.config:875: No python interpreter was found: disables
> Python support - please install python-devel/python-dev
>     Makefile.config:918: *** ERROR: No python interpreter needed for
> jevents generation. Install python or build with NO_JEVENTS=1..  Stop.
> 
> So these error messages sound like python is missing. And "python"
> is indeed missing, but "python3" is available.
> Hence I installed python-is-python3, but that turned out not to be
> sufficient.
> Hence I also installed python-dev-is-python3, and that fixed the issue,
> as python-dev-is-python3 depends on python3-dev, so the latter was
> installed, too.
> 
> After removing python-is-python3 and python-dev-is-python3, everything
> keeps on working.  But if you never installed python3-dev manually,
> and run "sudo apt autoremove", python3-dev is uninstalled, reintroducing
> the issue.
> 
> So just recomming to install python-dev-is-python3 in the error
> message should be sufficient?
> 
> What do you think?
> Thanks!

Thanks for looking at the issue.

I think the code was to deal with either python2 or python3 in the past
and we removed python2 support recently.  I don't know if any distro
made 'python' to refer python3 and removed 'python3' otherwise we can
just check python3.

Thanks,
Namhyung