Re: [PATCH v15 7/7] perf: Add more features to supported_features list

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Thu, Sep 05, 2024 at 08:03:08PM +0530, Aditya Gupta wrote:
> On 05/09/24 01:32, Arnaldo Carvalho de Melo wrote:
> 
> > On Thu, Sep 05, 2024 at 12:31:32AM +0530, Aditya Gupta wrote:
> > > As suggested in [1], add more feature names and corresponding names,
> > > based on the information in Makefile.config
> > > 
> > > The entries were added after seeing the corresponding -D option which is
> > > added to CFLAGS, based on the presence of a feature in Makefile.config,
> > > such as:
> > > 
> > >      ifeq ($(feature-file-handle), 1)
> > >        CFLAGS += -DHAVE_FILE_HANDLE
> > >      endif
> > > 
> > > For above feature 'file-handle', corresponding entry has been added to
> > > supported_features as below:
> > > 
> > >      FEATURE_STATUS("file-handle", HAVE_FILE_HANDLE)
> > > 
> > > [1]: https://lore.kernel.org/linux-perf-users/Zn7EvDbsnlbLXj4g@x1/
> > I'll remove this now because there were some that sounds really strange,
> > like:
> Okay.
> > acme@x1:~/git/perf-tools-next$ sudo su -
> > [sudo] password for acme:
> > root@x1:~# perf -vv
> > perf version 6.11.rc3.g15dc9f274b8e
> >                   glibc: [ OFF ]  # LIBC_SUPPORT
> > libslang-include-subdir: [ OFF ]  # HAVE_SLANG_INCLUDE_SUBDIR
> > 
> > 
> > The first one is the strange one, how come, no LIBC_SUPPORT? glibc?
> Debugged it:
> 
> 
> Output of `make` says glibc is there:
> 
> 
>     Auto-detecting system features:
> 
>     ...                                   ...
> 
>     ...                                   glibc: [ on  ]
> 
>     ...                                   ...
> 
>     ...                                  libelf: [ on  ]
> 
> 
> But, in Makefile.config, 'LIBC_SUPPORT' is only defined if libelf is NOT
> there:
> 
> 
>     ifeq ($(feature-libelf), 0)
>         ifeq ($(feature-glibc), 1)
>             LIBC_SUPPORT := 1
>         endif
>      ifeq ($(BIONIC),1)
>           LIBC_SUPPORT := 1
>       endif
> 
> 
> Hence since LIBC_SUPPORT is not defined, the check --feature command says
> glibc is OFF.
> 
> I think we can simply remove libc entry from the features array in this
> patch, as glibc is kind of obvious to be there if compilation worked.

Right, but please put some thought, if you have the time and
inclination, to try to make this LIBC_SUPPORT thing make sense, as it is
it is nuts :-)
 
> Meanwhile I will check all feature entries added in this patch again. I can
> post this patch as an independent patch.

Sure
 
> > The second looks irrelevant, I'll see.
> 
> Sure.

Thanks!

- Arnaldo