From patchwork Fri Dec 10 14:16:48 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 12669635 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2EF8CC433F5 for ; Fri, 10 Dec 2021 14:01:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239184AbhLJOFN (ORCPT ); Fri, 10 Dec 2021 09:05:13 -0500 Received: from szxga01-in.huawei.com ([45.249.212.187]:32909 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239225AbhLJOFN (ORCPT ); Fri, 10 Dec 2021 09:05:13 -0500 Received: from dggpeml500025.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4J9Xcy2fJtzcbsj; Fri, 10 Dec 2021 22:01:22 +0800 (CST) Received: from huawei.com (10.175.124.27) by dggpeml500025.china.huawei.com (7.185.36.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Fri, 10 Dec 2021 22:01:35 +0800 From: Hou Tao To: Alexei Starovoitov CC: Martin KaFai Lau , Yonghong Song , Daniel Borkmann , Andrii Nakryiko , , , Subject: [PATCH bpf-next v2 0/4] introduce bpf_strncmp() helper Date: Fri, 10 Dec 2021 22:16:48 +0800 Message-ID: <20211210141652.877186-1-houtao1@huawei.com> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpeml500025.china.huawei.com (7.185.36.35) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net 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