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From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Hou Tao <houtao1@huawei.com>, Daniel Xu <dxu@dxuuu.xyz>
Subject: [PATCHv2 bpf-next 0/9] bpf: Add missed stats for kprobes
Date: Thu,  7 Sep 2023 09:13:02 +0200	[thread overview]
Message-ID: <20230907071311.254313-1-jolsa@kernel.org> (raw)

hi,
at the moment we can't retrieve the number of missed kprobe
executions and subsequent execution of BPF programs.

This patchset adds:
  - counting of missed execution on attach layer for:
    . kprobes attached through perf link (kprobe/ftrace)
    . kprobes attached through kprobe.multi link (fprobe)
  - counting of recursion_misses for BPF kprobe programs


It's still technically possible to create kprobe without perf link (using
SET_BPF perf ioctl) in which case we don't have a way to retrieve the kprobe's
'missed' count. However both libbpf and cilium/ebpf libraries use perf link
if it's available, and for old kernels without perf link support we can use
BPF program to retrieve the kprobe missed count.

v2 changes:
  - rename bpf_prog_missed_array to bpf_prog_inc_misses_counters [Alexei]
  - add missing space to 'missed' output [Quentin]
  - drop runtime stats changes [Hou Tao]
  - add common helper for kprobe missed stats [Hou Tao]
  - add test for tracepoint recursion missed counts [Hou Tao]

Also available at:
  https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
  bpf/missed_stats

thanks,
jirka


---
Jiri Olsa (9):
      bpf: Count stats for kprobe_multi programs
      bpf: Add missed value to kprobe_multi link info
      bpf: Add missed value to kprobe perf link info
      bpf: Count missed stats in trace_call_bpf
      bpftool: Display missed count for kprobe_multi link
      bpftool: Display missed count for kprobe perf link
      selftests/bpf: Add test for missed counts of perf event link kprobe
      selftests/bpf: Add test for recursion counts of perf event link kprobe
      selftests/bpf: Add test for recursion counts of perf event link tracepoint

 include/linux/bpf.h                                         |  16 ++++++++++++++++
 include/linux/trace_events.h                                |   6 ++++--
 include/uapi/linux/bpf.h                                    |   2 ++
 kernel/bpf/syscall.c                                        |  14 ++++++++------
 kernel/trace/bpf_trace.c                                    |  10 ++++++++--
 kernel/trace/trace_kprobe.c                                 |  14 +++++++++++---
 tools/bpf/bpftool/link.c                                    |   6 ++++++
 tools/include/uapi/linux/bpf.h                              |   2 ++
 tools/testing/selftests/bpf/DENYLIST.aarch64                |   1 +
 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c       |   5 +++++
 tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h |   2 ++
 tools/testing/selftests/bpf/prog_tests/missed.c             | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tools/testing/selftests/bpf/progs/missed_kprobe.c           |  30 ++++++++++++++++++++++++++++++
 tools/testing/selftests/bpf/progs/missed_kprobe_recursion.c |  48 ++++++++++++++++++++++++++++++++++++++++++++++++
 tools/testing/selftests/bpf/progs/missed_tp_recursion.c     |  41 +++++++++++++++++++++++++++++++++++++++++
 15 files changed, 322 insertions(+), 13 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/missed.c
 create mode 100644 tools/testing/selftests/bpf/progs/missed_kprobe.c
 create mode 100644 tools/testing/selftests/bpf/progs/missed_kprobe_recursion.c
 create mode 100644 tools/testing/selftests/bpf/progs/missed_tp_recursion.c

             reply	other threads:[~2023-09-07  7:13 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-07  7:13 Jiri Olsa [this message]
2023-09-07  7:13 ` [PATCHv2 bpf-next 1/9] bpf: Count stats for kprobe_multi programs Jiri Olsa
2023-09-07 18:09   ` Song Liu
2023-09-07  7:13 ` [PATCHv2 bpf-next 2/9] bpf: Add missed value to kprobe_multi link info Jiri Olsa
2023-09-07 18:15   ` Song Liu
2023-09-07  7:13 ` [PATCHv2 bpf-next 3/9] bpf: Add missed value to kprobe perf " Jiri Olsa
2023-09-07 18:40   ` Song Liu
2023-09-08 11:43     ` Jiri Olsa
2023-09-08 16:49       ` Song Liu
2023-09-10 18:54         ` Jiri Olsa
2023-09-08 23:22       ` Andrii Nakryiko
2023-09-08 23:32         ` Song Liu
2023-09-08 23:44           ` Andrii Nakryiko
2023-09-10 18:54         ` Jiri Olsa
2023-09-07  7:13 ` [PATCHv2 bpf-next 4/9] bpf: Count missed stats in trace_call_bpf Jiri Olsa
2023-09-07 18:46   ` Song Liu
2023-09-07  7:13 ` [PATCHv2 bpf-next 5/9] bpftool: Display missed count for kprobe_multi link Jiri Olsa
2023-09-07  7:13 ` [PATCHv2 bpf-next 6/9] bpftool: Display missed count for kprobe perf link Jiri Olsa
2023-09-07  7:13 ` [PATCHv2 bpf-next 7/9] selftests/bpf: Add test for missed counts of perf event link kprobe Jiri Olsa
2023-09-07 18:52   ` Song Liu
2023-09-08 23:25   ` Andrii Nakryiko
2023-09-10 18:54     ` Jiri Olsa
2023-09-07  7:13 ` [PATCHv2 bpf-next 8/9] selftests/bpf: Add test for recursion " Jiri Olsa
2023-09-07 18:55   ` Song Liu
2023-09-14  7:56     ` Jiri Olsa
2023-09-07  7:13 ` [PATCHv2 bpf-next 9/9] selftests/bpf: Add test for recursion counts of perf event link tracepoint Jiri Olsa
2023-09-07 19:00   ` Song Liu

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