Re: [PATCH 1/2] perf build: Use pkg-config for feature check for libtrace{event,fs}

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

On Fri, Jun 28, 2024 at 12:27:11PM +0200, Guilherme Amadio wrote:
> On Fri, Jun 28, 2024 at 09:13:43AM +0200, Thorsten Leemhuis wrote:
> > On 06.06.24 17:33, amadio@gentoo.org wrote:
> > > From: Guilherme Amadio <amadio@gentoo.org>
> > > 
> > > Needed to add required include directories for the feature detection
> > > to succeed. The header tracefs.h is installed either into the include
> > > directory /usr/include/tracefs/tracefs.h when using the Makefile, or
> > > into /usr/include/libtracefs/tracefs.h when using meson to build
> > > libtracefs. The header tracefs.h uses #include <event-parse.h> from
> > > libtraceevent, so pkg-config needs to pick the correct include directory
> > > for libtracefs and add the one for libtraceevent to succeed.
> > > 
> > > Note that in baa2ca59ec1e31ccbe3f24ff0368152b36f68720 the variable
> > > LIBTRACEEVENT_DIR was introduced, and now the method to compile against
> > > non-standard locations requires PKG_CONFIG_PATH to be set instead, which
> > > works for both libtraceevent and libtracefs.
> > > 
> > > Signed-off-by: Guilherme Amadio <amadio@gentoo.org>
> > > Cc: Ian Rogers <irogers@google.com>
> > 
> > Since this patch landed in Linux next as 0f0e1f44569061 ("perf build:
> > Use pkg-config for feature check for libtrace{event,fs}") my vanilla 
> > -next build using the RPM spec file from Fedora fails. I'm not sure if
> > it causes my problems, but it looks likely.
> 
> Thank you for reporting. I think we need to use similar checks in the
> tools/verification/rv/Makefile.config, as it seems the problem comes
> from there:
> 
> + pushd tools/verification/rv/
> kernel.spec:3000: build rv
> ... (compile command lines removed)
> 
> Auto-detecting system features:
> ...                           libtraceevent: [ on  ]
> ...                              libtracefs: [ OFF ]
> 
> libtracefs is missing. Please install libtracefs-dev/libtracefs-devel
> Makefile.config:46: *** Please, check the errors above..  Stop.
> error: Bad exit status from /var/tmp/rpm-tmp.yNun6A (%build)
> 
> I will submit a patch to fix it.

I noticed something related, but in my case the build proceeded, giving
these warings:

Package libtracefs was not found in the pkg-config search path.
Perhaps you should add the directory containing `libtracefs.pc'
to the PKG_CONFIG_PATH environment variable
Package 'libtracefs', required by 'virtual:world', not found
Package libtracefs was not found in the pkg-config search path.
Perhaps you should add the directory containing `libtracefs.pc'
to the PKG_CONFIG_PATH environment variable
Package 'libtracefs', required by 'virtual:world', not found

Auto-detecting system features:
...                                   dwarf: [ on  ]
...                      dwarf_getlocations: [ on  ]
...                                   glibc: [ on  ]
...                                  libbfd: [ on  ]
...                          libbfd-buildid: [ on  ]
...                                  libcap: [ on  ]
...                                  libelf: [ on  ]
...                                 libnuma: [ on  ]
...                  numa_num_possible_cpus: [ on  ]
...                                 libperl: [ on  ]
...                               libpython: [ on  ]
...                               libcrypto: [ on  ]
...                               libunwind: [ on  ]
...                      libdw-dwarf-unwind: [ on  ]
...                             libcapstone: [ on  ]
...                                    zlib: [ on  ]
...                                    lzma: [ on  ]
...                               get_cpuid: [ on  ]
...                                     bpf: [ on  ]
...                                  libaio: [ on  ]
...                                 libzstd: [ on  ]

⬢[acme@toolbox perf-tools-next]$ rpm -qa | grep tracefs
⬢[acme@toolbox perf-tools-next]$ rpm -qa | grep traceevent
libtraceevent-1.7.2-3.fc39.x86_64
libtraceevent-devel-1.7.2-3.fc39.x86_64
⬢[acme@toolbox perf-tools-next]$

- Arnaldo

 
> Best regards,
> -Guilherme
> 
> > 
> > A log of a failed build can be found here:
> > https://download.copr.fedorainfracloud.org/results/@kernel-vanilla/next/fedora-rawhide-x86_64/07670271-next-next-all/builder-live.log.gz
> > 
> > The gist:
> > """
> > 
> > Auto-detecting system features:
> > ...                           libtraceevent: [ on  ]
> > ...                              libtracefs: [ OFF ]
> > 
> > libtracefs is missing. Please install libtracefs-dev/libtracefs-devel
> > Makefile.config:46: *** Please, check the errors above..  Stop.
> > error: Bad exit status from /var/tmp/rpm-tmp.yNun6A (%build)
> > """
> > 
> > But libtracefs-devel is installed and pkgconfig works (output from
> > another machine):
> > 
> > $ pkgconf --cflags libtracefs
> > -I/usr/include/tracefs -I/usr/include/traceevent
> > 
> > From a *quick* looks it seems those flags are not picked up when
> > building tools/verification/rv/feature/test-libtracefs.bin 
> > 
> > """
> > + pkg-config --cflags libtraceevent
> > gcc  -MD -Wall -Werror -o /home/thl/usr/tmp/linux-next/tools/verification/rv/feature/test-libtracefs.bin test-libtracefs.c -ggdb   > /home/thl/usr/tmp/linux-next/tools/verification/rv/feature/test-libtracefs.make.output 2>&1 -I/usr/include/traceevent  -ltracefs
> > + gcc -MD -Wall -Werror -o /home/thl/usr/tmp/linux-next/tools/verification/rv/feature/test-libtracefs.bin test-libtracefs.c -ggdb -I/usr/include/traceevent -ltracefs
> > make: *** [Makefile:216: /home/thl/usr/tmp/linux-next/tools/verification/rv/feature/test-libtracefs.bin] Error 1
> > make: Leaving directory '/home/thl/usr/tmp/linux-next/tools/build/feature'
> > """
> > 
> > And
> > 
> > """
> > $ cat /home/thl/usr/tmp/linux-next/tools/verification/rv/feature/test-libtracefs.make.output 
> > test-libtracefs.c:2:10: fatal error: tracefs.h: No such file or directory
> >     2 | #include <tracefs.h>
> >       |          ^~~~~~~~~~~
> > compilation terminated.
> > """
> > 
> > Then I ran out of time looking where it might missing and decided to write
> > this mail instead.
> > 
> > Ciao, Thorsten
> > 
> > 
> > > ---
> > >  tools/build/feature/test-libtracefs.c |  2 +-
> > >  tools/perf/Makefile.config            | 27 +++++++++++++--------------
> > >  2 files changed, 14 insertions(+), 15 deletions(-)
> > > 
> > > diff --git a/tools/build/feature/test-libtracefs.c b/tools/build/feature/test-libtracefs.c
> > > index 8eff16c0c10b..29a757a7d848 100644
> > > --- a/tools/build/feature/test-libtracefs.c
> > > +++ b/tools/build/feature/test-libtracefs.c
> > > @@ -1,5 +1,5 @@
> > >  // SPDX-License-Identifier: GPL-2.0
> > > -#include <tracefs/tracefs.h>
> > > +#include <tracefs.h>
> > >
> > > [...]