Re: [PATCH v3 0/2] perf build: Support building BPF skeletons with bpf-gcc

[Ian Rogers]

On Thu, Oct 22, 2026 at 1:46 PM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> Currently the perf build requires clang (>= 12.0.1) to compile BPF
> skeleton programs (.bpf.c -> .bpf.o). bpf-gcc (>= 14.0.0) also supports
> BPF CO-RE and BTF generation and is already supported in
> tools/testing/selftests/bpf/Makefile.
>
> This series updates the perf build to support both clang and bpf-gcc:
> - Patch 1 updates Makefile.config, Makefile.perf, and bpf_skel.mak to
>   prefer bpf-gcc when building perf with GCC (CC_NO_CLANG=1) and clang
>   when building with Clang/LLVM (CC_NO_CLANG=0), while respecting
>   explicit BPF_GCC=... or CLANG=... command-line overrides and falling
>   back to whichever compiler is available.
> - Patch 2 adds make_bpf_skel_clang and make_bpf_skel_bpf_gcc build-test
>   targets to tools/perf/tests/make, reuses tools/build/Makefile.feature
>   for feature detection, and verifies with
>   'perf check -q feature bpf_skeletons' that BPF skeleton support is
>   enabled (or disabled for make_no_bpf_skel) as expected.
>
> v3: Reuse tools/build/Makefile.feature and tools/scripts/utilities.mak
>     in tools/perf/tests/make rather than open-coding compiler feature
>     probes, and explicitly check for exit code 1 from 'perf check' in
>     make_no_bpf_skel so crashes are not masked by shell negation.
> v2: Pass only -dumpfullversion when querying BPF_GCC_VERSION, guard
>     against an empty version string, and fix version-ge3 / version-lt3
>     in tools/scripts/utilities.mak so empty or <3-component version
>     strings do not shift awk fields and evaluate as false in version-lt3.
>
> Ian Rogers (2):
>   perf build: Support building BPF skeletons with bpf-gcc
>   perf test make: Add BPF skeleton build tests for clang and bpf-gcc

Ping. Just to note that the 2 patches are clean with Sashiko:
https://sashiko.dev/#/patchset/20261022204627.1813821-1-irogers%40google.com

Thanks,
Ian

>  tools/perf/Makefile.config     | 83 +++++++++++++++++++++++++++-------
>  tools/perf/Makefile.perf       |  8 +++-
>  tools/perf/bpf_skel.mak        | 36 ++++++++++-----
>  tools/perf/tests/make          | 71 ++++++++++++++++++++++------
>  tools/scripts/Makefile.include |  1 +
>  tools/scripts/utilities.mak    |  4 +-
>  6 files changed, 159 insertions(+), 44 deletions(-)
>
> --
> 2.56.0.307.g5fe7bd680c-goog
>