From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Wenbo Zhang <ethercflow@gmail.com>
Cc: bpf <bpf@vger.kernel.org>, Yonghong Song <yhs@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Networking <netdev@vger.kernel.org>
Subject: Re: [PATCH bpf-next v2] selftests/bpf: test for bpf_get_file_path() from raw tracepoint
Date: Fri, 1 Nov 2019 22:48:49 -0700 [thread overview]
Message-ID: <CAEf4Bzand8qSxqmryyxMNg3FNL-pgokJ4taRrtGq07rdbEjsbA@mail.gmail.com> (raw)
In-Reply-To: <20191101130817.11744-1-ethercflow@gmail.com>
On Fri, Nov 1, 2019 at 6:08 AM Wenbo Zhang <ethercflow@gmail.com> wrote:
>
> trace fstat events by raw tracepoint sys_enter:newfstat, and handle events
> only produced by fd2path_loadgen, the fd2path_loadgen call fstat on several
> different types of files to test bpf_get_file_path's feature.
> ---
Unless there is a real reason for all this complexity (in which case,
please spell it out in commit or comments), I think this could be so
much simpler.
- you don't have to use perf_buffer to pass data back, just use global data;
- you can add a filter for PID to only capture data triggered by test
process and avoid the noise;
- why all those set_affinity dances? Is it just because you used
existing perf_buffer test which did that to specifically test
perf_buffer delivering data across every CPU core? Seems like your
test doesn't care about that...
- do we really need a separate binary generating hundreds of syscalls?
It's hard to synchronize with test and it seems much simpler to just
trigger necessary syscalls synchronously from the test itself, no?
I have a bunch of more minutia nits, but most of them will go away if
you simplify your testing approach anyway, so I'll postpone them till
then.
> tools/testing/selftests/bpf/Makefile | 8 +-
> tools/testing/selftests/bpf/fd2path_loadgen.c | 75 ++++++++++
> .../selftests/bpf/prog_tests/get_file_path.c | 130 ++++++++++++++++++
> .../selftests/bpf/progs/test_get_file_path.c | 58 ++++++++
> 4 files changed, 269 insertions(+), 2 deletions(-)
> create mode 100644 tools/testing/selftests/bpf/fd2path_loadgen.c
> create mode 100644 tools/testing/selftests/bpf/prog_tests/get_file_path.c
> create mode 100644 tools/testing/selftests/bpf/progs/test_get_file_path.c
>
[...]
next prev parent reply other threads:[~2019-11-02 5:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-01 13:08 [PATCH bpf-next v2] selftests/bpf: test for bpf_get_file_path() from raw tracepoint Wenbo Zhang
2019-11-02 5:48 ` Andrii Nakryiko [this message]
2019-11-03 9:57 ` Wenbo Zhang
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