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Message-ID: <20211210141652.877186-1-houtao1@huawei.com>
Date: Fri, 10 Dec 2021 22:16:48 +0800
From: Hou Tao <houtao1@...wei.com>
To: Alexei Starovoitov <ast@...nel.org>
CC: Martin KaFai Lau <kafai@...com>, Yonghong Song <yhs@...com>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andrii@...nel.org>, <netdev@...r.kernel.org>,
<bpf@...r.kernel.org>, <houtao1@...wei.com>
Subject: [PATCH bpf-next v2 0/4] introduce bpf_strncmp() helper
Hi,
The motivation for introducing bpf_strncmp() helper comes from
two aspects:
(1) clang doesn't always replace strncmp() automatically
In tracing program, sometimes we need to using a home-made
strncmp() to check whether or not the file name is expected.
(2) the performance of home-made strncmp is not so good
As shown in the benchmark in patch #4, the performance of
bpf_strncmp() helper is 18% or 33% better than home-made strncmp()
under x86-64 or arm64 when the compared string length is 64. When
the string length grows to 4095, the performance win will be
179% or 600% under x86-64 or arm64.
Any comments are welcome.
Regards,
Tao
Change Log:
v2:
* rebased on bpf-next
* drop patch "selftests/bpf: factor out common helpers for benchmarks"
(suggested by Andrii)
* remove unnecessary inline functions and add comments for programs which
will be rejected by verifier in patch 4 (suggested by Andrii)
* rename variables used in will-fail programs to clarify the purposes.
v1: https://lore.kernel.org/bpf/20211130142215.1237217-1-houtao1@huawei.com
* change API to bpf_strncmp(const char *s1, u32 s1_sz, const char *s2)
* add benchmark refactor and benchmark between bpf_strncmp() and strncmp()
RFC: https://lore.kernel.org/bpf/20211106132822.1396621-1-houtao1@huawei.com/
Hou Tao (4):
bpf: add bpf_strncmp helper
selftests/bpf: fix checkpatch error on empty function parameter
selftests/bpf: add benchmark for bpf_strncmp() helper
selftests/bpf: add test cases for bpf_strncmp()
include/linux/bpf.h | 1 +
include/uapi/linux/bpf.h | 11 ++
kernel/bpf/helpers.c | 16 ++
tools/include/uapi/linux/bpf.h | 11 ++
tools/testing/selftests/bpf/Makefile | 4 +-
tools/testing/selftests/bpf/bench.c | 8 +-
tools/testing/selftests/bpf/bench.h | 9 +-
.../selftests/bpf/benchs/bench_count.c | 2 +-
.../selftests/bpf/benchs/bench_rename.c | 16 +-
.../selftests/bpf/benchs/bench_ringbufs.c | 14 +-
.../selftests/bpf/benchs/bench_strncmp.c | 161 +++++++++++++++++
.../selftests/bpf/benchs/bench_trigger.c | 24 +--
.../selftests/bpf/benchs/run_bench_strncmp.sh | 12 ++
.../selftests/bpf/prog_tests/test_strncmp.c | 167 ++++++++++++++++++
.../selftests/bpf/progs/strncmp_bench.c | 50 ++++++
.../selftests/bpf/progs/strncmp_test.c | 54 ++++++
16 files changed, 526 insertions(+), 34 deletions(-)
create mode 100644 tools/testing/selftests/bpf/benchs/bench_strncmp.c
create mode 100755 tools/testing/selftests/bpf/benchs/run_bench_strncmp.sh
create mode 100644 tools/testing/selftests/bpf/prog_tests/test_strncmp.c
create mode 100644 tools/testing/selftests/bpf/progs/strncmp_bench.c
create mode 100644 tools/testing/selftests/bpf/progs/strncmp_test.c
--
2.29.2
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