From: Alexei Starovoitov Date: Sun, 12 Dec 2021 01:40:23 +0000 (-0800) Subject: Merge branch 'introduce bpf_strncmp() helper' X-Git-Tag: v5.19~1494^2~92^2~43 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=84ef3f0bb72dfcdeb7ff3e5335882f6084381437;p=mirror_ubuntu-kernels.git Merge branch 'introduce bpf_strncmp() helper' Hou Tao says: ==================== 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/ ==================== Signed-off-by: Alexei Starovoitov --- 84ef3f0bb72dfcdeb7ff3e5335882f6084381437