Re: [PATCH v4 bpf-next 0/4] libbpf: add perf buffer abstraction and API

[Daniel Borkmann <daniel@iogearbox.net>]

On 06/30/2019 08:51 AM, Andrii Nakryiko wrote:
> This patchset adds a high-level API for setting up and polling perf buffers
> associated with BPF_MAP_TYPE_PERF_EVENT_ARRAY map. Details of APIs are
> described in corresponding commit.
> 
> Patch #1 adds a set of APIs to set up and work with perf buffer.
> Patch #2 enhances libbpf to support auto-setting PERF_EVENT_ARRAY map size.
> Patch #3 adds test.
> Patch #4 converts bpftool map event_pipe to new API.
> 
> v3->v4:
> - fixed bpftool event_pipe cmd error handling (Jakub);
> 
> v2->v3:
> - added perf_buffer__new_raw for more low-level control;
> - converted bpftool map event_pipe to new API (Daniel);
> - fixed bug with error handling in create_maps (Song);
> 
> v1->v2:
> - add auto-sizing of PERF_EVENT_ARRAY maps;
> 
> Andrii Nakryiko (4):
>   libbpf: add perf buffer API
>   libbpf: auto-set PERF_EVENT_ARRAY size to number of CPUs
>   selftests/bpf: test perf buffer API
>   tools/bpftool: switch map event_pipe to libbpf's perf_buffer
> 
>  tools/bpf/bpftool/map_perf_ring.c             | 201 +++------
>  tools/lib/bpf/libbpf.c                        | 397 +++++++++++++++++-
>  tools/lib/bpf/libbpf.h                        |  49 +++
>  tools/lib/bpf/libbpf.map                      |   4 +
>  .../selftests/bpf/prog_tests/perf_buffer.c    |  94 +++++
>  .../selftests/bpf/progs/test_perf_buffer.c    |  29 ++
>  6 files changed, 630 insertions(+), 144 deletions(-)
>  create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_buffer.c
>  create mode 100644 tools/testing/selftests/bpf/progs/test_perf_buffer.c

Hm, set looks good, but this does not apply cleanly. Please rebase against
bpf-next and resubmit. Please also update tools/lib/bpf/README.rst with regards
to the perf_buffer__ prefix. While at it, you could also address Jakub's comment.

Thanks,
Daniel