Re: [PATCH v3 1/2] perf: support build BPF skeletons with perf

Jiri Olsa
2020-12-09T17:06:50Z

On Tue, Dec 08, 2020 at 10:16:45AM -0800, Song Liu wrote:
> BPF programs are useful in perf to profile BPF programs. BPF skeleton is
> by far the easiest way to write BPF tools. Enable building BPF skeletons
> in util/bpf_skel. A dummy bpf skeleton is added. More bpf skeletons will
> be added for different use cases.
>
> Signed-off-by: Song Liu <songliubraving@fb.com>

one nit below, but other than that:

Acked-by: Jiri Olsa <jolsa@redhat.com>

thanks,
jirka

> ---
> tools/bpf/bpftool/Makefile | 3 ++
> tools/build/Makefile.feature | 4 ++-
> tools/perf/Makefile.config | 9 ++++++
> tools/perf/Makefile.perf | 48 +++++++++++++++++++++++++++--
> tools/perf/util/bpf_skel/.gitignore | 3 ++
> tools/scripts/Makefile.include | 1 +
> 6 files changed, 65 insertions(+), 3 deletions(-)
> create mode 100644 tools/perf/util/bpf_skel/.gitignore
>
> diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
> index f897cb5fb12d0..390af1a52601e 100644
> --- a/tools/bpf/bpftool/Makefile
> +++ b/tools/bpf/bpftool/Makefile
> @@ -139,6 +139,9 @@ endif
> BPFTOOL_BOOTSTRAP := $(BOOTSTRAP_OUTPUT)bpftool
>
> BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o)
> +
> +bootstrap: $(BPFTOOL_BOOTSTRAP)
> +
> OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
>
> VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \
> diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
> index 97cbfb31b7625..74e255d58d8d0 100644
> --- a/tools/build/Makefile.feature
> +++ b/tools/build/Makefile.feature
> @@ -99,7 +99,9 @@ FEATURE_TESTS_EXTRA := \
> clang \
> libbpf \
> libpfm4 \
> - libdebuginfod
> + libdebuginfod \
> + clang-bpf-co-re
> +
>
> FEATURE_TESTS ?= $(FEATURE_TESTS_BASIC)
>
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index ce8516e4de34f..fe234b8bfeefb 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -621,6 +621,15 @@ ifndef NO_LIBBPF
> endif
> endif
>
> +ifdef BUILD_BPF_SKEL
> + $(call feature_check,clang-bpf-co-re)
> + ifeq ($(feature-clang-bpf-co-re), 0)
> + dummy := $(error Error: clang too old. Please install recent clang)
> + endif
> + $(call detected,CONFIG_PERF_BPF_SKEL)
> + CFLAGS += -DBUILD_BPF_SKEL

sorry I did not notice before, but we use HAVE_* name style for these C macros

HAVE_BPF_SKEL should fit

> +endif
> +
> dwarf-post-unwind := 1
> dwarf-post-unwind-text := BUG
>
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index 62f3deb1d3a8b..9ea9047a621bc 100644
> --- a/tools/perf/Makefile.perf

SNIP