Re: [PATCH v2 4/4] perf: add test for PERF_RECORD_BPF_METADATA collection

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On Thu, Jun 5, 2025 at 4:39 PM Blake Jones <blakejones@xxxxxxxxxx> wrote:
>
> This is an end-to-end test for the PERF_RECORD_BPF_METADATA support.
> It adds a new "bpf_metadata_perf_version" variable to perf's BPF programs,
> so that when they are loaded, there will be at least one BPF program with
> some metadata to parse. The test invokes "perf record" in a way that loads
> one of those BPF programs, and then sifts through the output to find its
> BPF metadata.
>
> Signed-off-by: Blake Jones <blakejones@xxxxxxxxxx>
> ---
>  tools/perf/Makefile.perf                    |  3 +-
>  tools/perf/tests/shell/test_bpf_metadata.sh | 76 +++++++++++++++++++++
>  tools/perf/util/bpf_skel/perf_version.h     | 17 +++++
>  3 files changed, 95 insertions(+), 1 deletion(-)
>  create mode 100755 tools/perf/tests/shell/test_bpf_metadata.sh
>  create mode 100644 tools/perf/util/bpf_skel/perf_version.h
>
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index d4c7031b01a7..4f292edeca5a 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -1250,8 +1250,9 @@ else
>         $(Q)cp "$(VMLINUX_H)" $@
>  endif
>
> -$(SKEL_TMP_OUT)/%.bpf.o: util/bpf_skel/%.bpf.c $(LIBBPF) $(SKEL_OUT)/vmlinux.h | $(SKEL_TMP_OUT)
> +$(SKEL_TMP_OUT)/%.bpf.o: util/bpf_skel/%.bpf.c $(OUTPUT)PERF-VERSION-FILE util/bpf_skel/perf_version.h $(LIBBPF) $(SKEL_OUT)/vmlinux.h | $(SKEL_TMP_OUT)
>         $(QUIET_CLANG)$(CLANG) -g -O2 --target=bpf $(CLANG_OPTIONS) $(BPF_INCLUDE) $(TOOLS_UAPI_INCLUDE) \
> +         -include $(OUTPUT)PERF-VERSION-FILE -include util/bpf_skel/perf_version.h \
>           -c $(filter util/bpf_skel/%.bpf.c,$^) -o $@
>
>  $(SKEL_OUT)/%.skel.h: $(SKEL_TMP_OUT)/%.bpf.o | $(BPFTOOL)
> diff --git a/tools/perf/tests/shell/test_bpf_metadata.sh b/tools/perf/tests/shell/test_bpf_metadata.sh
> new file mode 100755
> index 000000000000..11df592fb661
> --- /dev/null
> +++ b/tools/perf/tests/shell/test_bpf_metadata.sh
> @@ -0,0 +1,76 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0

The 2nd line in a shell test script is taken to be the name of the test, so
```
$ perf test list 108
108: SPDX-License-Identifier: GPL-2.0
```

> +#
> +# BPF metadata collection test.

This should be on line 2 instead.

Thanks,
Ian

> +
> +set -e
> +
> +err=0
> +perfdata=$(mktemp /tmp/__perf_test.perf.data.XXXXX)
> +
> +cleanup() {
> +       rm -f "${perfdata}"
> +       rm -f "${perfdata}".old
> +       trap - EXIT TERM INT
> +}
> +
> +trap_cleanup() {
> +       cleanup
> +       exit 1
> +}
> +trap trap_cleanup EXIT TERM INT
> +
> +test_bpf_metadata() {
> +       echo "Checking BPF metadata collection"
> +
> +       if ! perf check -q feature libbpf-strings ; then
> +               echo "Basic BPF metadata test [skipping - not supported]"
> +               err=0
> +               return
> +       fi
> +
> +       # This is a basic invocation of perf record
> +       # that invokes the perf_sample_filter BPF program.
> +       if ! perf record -e task-clock --filter 'ip > 0' \
> +                        -o "${perfdata}" sleep 1 2> /dev/null
> +       then
> +               echo "Basic BPF metadata test [Failed record]"
> +               err=1
> +               return
> +       fi
> +
> +       # The BPF programs that ship with "perf" all have the following
> +       # variable defined at compile time:
> +       #
> +       #   const char bpf_metadata_perf_version[] SEC(".rodata") = <...>;
> +       #
> +       # This invocation looks for a PERF_RECORD_BPF_METADATA event,
> +       # and checks that its content contains the string given by
> +       # "perf version".
> +       VERS=$(perf version | awk '{print $NF}')
> +       if ! perf script --show-bpf-events -i "${perfdata}" | awk '
> +               /PERF_RECORD_BPF_METADATA.*perf_sample_filter/ {
> +                       header = 1;
> +               }
> +               /^ *entry/ {
> +                       if (header) { header = 0; entry = 1; }
> +               }
> +               $0 !~ /^ *entry/ {
> +                       entry = 0;
> +               }
> +               /perf_version/ {
> +                       if (entry) print $NF;
> +               }
> +       ' | egrep "$VERS" > /dev/null
> +       then
> +               echo "Basic BPF metadata test [Failed invalid output]"
> +               err=1
> +               return
> +       fi
> +       echo "Basic BPF metadata test [Success]"
> +}
> +
> +test_bpf_metadata
> +
> +cleanup
> +exit $err
> diff --git a/tools/perf/util/bpf_skel/perf_version.h b/tools/perf/util/bpf_skel/perf_version.h
> new file mode 100644
> index 000000000000..1ed5b2e59bf5
> --- /dev/null
> +++ b/tools/perf/util/bpf_skel/perf_version.h
> @@ -0,0 +1,17 @@
> +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
> +
> +#ifndef __PERF_VERSION_H__
> +#define __PERF_VERSION_H__
> +
> +#include "vmlinux.h"
> +#include <bpf/bpf_helpers.h>
> +
> +/*
> + * This is used by tests/shell/record_bpf_metadata.sh
> + * to verify that BPF metadata generation works.
> + *
> + * PERF_VERSION is defined by a build rule at compile time.
> + */
> +const char bpf_metadata_perf_version[] SEC(".rodata") = PERF_VERSION;
> +
> +#endif /* __PERF_VERSION_H__ */
> --
> 2.50.0.rc0.604.gd4ff7b7c86-goog
>





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