hi,
sending additional fix for symbol resolving in kprobe multi link
requested by Alexei and Andrii [1].
This speeds up bpftrace kprobe attachment, when using pure symbols
(3344 symbols) to attach:
Before:
# 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% )
v2 changes (first version [2]):
- removed the 2 seconds check [Alexei]
- moving/forcing symbols sorting out of kallsyms_lookup_names function [Alexei]
- skipping one array allocation and copy_from_user [Andrii]
- several small fixes [Masami,Andrii]
- build fix [kernel test robot]
thanks,
jirka
[1] https://lore.kernel.org/bpf/CAEf4BzZtQaiUxQ-sm_hH2qKPRaqGHyOfEsW96DxtBHRaKLoL3Q@xxxxxxxxxxxxxx/
[2] https://lore.kernel.org/bpf/20220407125224.310255-1-jolsa@xxxxxxxxxx/
---
Jiri Olsa (4):
kallsyms: Add kallsyms_lookup_names function
fprobe: Resolve symbols with kallsyms_lookup_names
bpf: Resolve symbols with kallsyms_lookup_names for kprobe multi link
selftests/bpf: Add attach bench test
include/linux/kallsyms.h | 6 ++++++
kernel/kallsyms.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
kernel/trace/bpf_trace.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------------------------
kernel/trace/fprobe.c | 32 ++++++++++++--------------------
tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/progs/kprobe_multi_empty.c | 12 ++++++++++++
6 files changed, 302 insertions(+), 67 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/kprobe_multi_empty.c
