bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link
authorJiri Olsa <jolsa@kernel.org>
Tue, 10 May 2022 12:26:15 +0000 (14:26 +0200)
committerAlexei Starovoitov <ast@kernel.org>
Tue, 10 May 2022 21:42:06 +0000 (14:42 -0700)
commit0236fec57a15dc2a068dfe4488e0c2ab4559b1ec
treee8e79d70b7934168f24cff2eb0adfe43ec8aeee2
parent8be9253344a1d8cd91b22655e55de41e3288aaf9
bpf: Resolve symbols with ftrace_lookup_symbols for kprobe multi link

Using kallsyms_lookup_names function to speed up symbols lookup in
kprobe multi link attachment and replacing with it the current
kprobe_multi_resolve_syms function.

This speeds up bpftrace kprobe attachment:

  # perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* {  } i:ms:1 { exit(); }'
  ...
  6.5681 +- 0.0225 seconds time elapsed  ( +-  0.34% )

After:

  # perf stat -r 5 -e cycles ./src/bpftrace -e 'kprobe:x* {  } i:ms:1 { exit(); }'
  ...
  0.5661 +- 0.0275 seconds time elapsed  ( +-  4.85% )

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20220510122616.2652285-5-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
kernel/trace/bpf_trace.c