Re: [PATCH v2 2/3] perf build: Remove libbpf pre-1.0 feature tests

[Ian Rogers]

On Mon, Mar 13, 2023 at 2:38 PM Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
>
> Em Mon, Mar 13, 2023 at 06:10:40PM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Sun, Jan 15, 2023 at 05:01:14PM -0800, Ian Rogers escreveu:
> > > The feature tests were necessary for libbpf pre-1.0, but as the libbpf
> > > implies at least 1.0 we can remove these now.
> >
> > So I added this:
> >
> > diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> > index 8b0bd3aa018ef166..b715cd4f43f4a014 100644
> > --- a/tools/perf/Makefile.config
> > +++ b/tools/perf/Makefile.config
> > @@ -580,7 +580,7 @@ ifndef NO_LIBELF
> >            EXTLIBS += -lbpf
> >            $(call detected,CONFIG_LIBBPF_DYNAMIC)
> >          else
> > -          dummy := $(error Error: No libbpf devel library found, please install libbpf-devel);
> > +          dummy := $(error Error: No libbpf devel library found or older than v1.0, please install/update libbpf-devel);
> >          endif
> >        else
> >          # Libbpf will be built as a static library from tools/lib/bpf.
> >
> > To better reflect the failure reason:
> >
> > ⬢[acme@toolbox perf-tools-next]$ cat /tmp/build/perf-tools-next/feature/test-libbpf.make.output
> > test-libbpf.c:5:2: error: #error At least libbpf 1.0 is required for Linux tools.
> >     5 | #error At least libbpf 1.0 is required for Linux tools.
> >       |  ^~~~~
> > ⬢[acme@toolbox perf-tools-next]$ rpm -q libbpf-devel
> > libbpf-devel-0.8.0-2.fc37.x86_64
> > ⬢[acme@toolbox perf-tools-next]$
> >
> > I'll see if I can make the build test conditional on libbpf being >= 1.0
>
> I'm trying with this:
>
> ⬢[acme@toolbox libbpf]$ git log --oneline -1 9476dce6fe905a6bf1d4c483f7b2b8575c4ffb2d
> 9476dce6fe905a6b libbpf: remove deprecated low-level APIs
> ⬢[acme@toolbox libbpf]$ git tag --contains 9476dce6fe905a6bf1d4c483f7b2b8575c4ffb2d
> v1.0.0
> v1.0.1
> v1.1.0
> ⬢[acme@toolbox libbpf]$
>
> diff --git a/tools/perf/tests/make b/tools/perf/tests/make
> index 531324c3dab594e1..f866c58b916f4d7a 100644
> --- a/tools/perf/tests/make
> +++ b/tools/perf/tests/make
> @@ -63,6 +63,7 @@ endif
>
>  has = $(shell which $1 2>/dev/null)
>  python_perf_so := $(shell $(MAKE) python_perf_target|grep "Target is:"|awk '{print $$3}')
> +old_libbpf := $(shell grep -q LIBBPF_DEPRECATED /usr/include/bpf/bpf.h)

I think this could also be:
old_libbpf := $(shell grep MAJOR /usr/include/bpf/libbpf_version.h
2>&1 |grep -q  0)
Which may be a bit more intention revealing and future proof.

Thanks,
Ian

>  # standard single make variable specified
>  make_clean_all      := clean all
> @@ -151,7 +152,9 @@ run += make_no_libaudit
>  run += make_no_libbionic
>  run += make_no_auxtrace
>  run += make_no_libbpf
> +ifneq ($(old_libbpf),)
>  run += make_libbpf_dynamic
> +endif
>  run += make_no_libbpf_DEBUG
>  run += make_no_libcrypto
>  run += make_no_sdt