On Fri, Dec 10, 2021 at 6:01 AM Hou Tao <houtao1@xxxxxxxxxx> wrote: > > 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. Applied. Thanks
