On Tue, Nov 30, 2021 at 6:07 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. I think 'home made' strncmp could have been written differently. I bet in bpf assembly it would be much closer in performance if not the same, but the helper is useful. The patch set doesn't apply cleanly. Pls respin.
