hi,
adding helpers for trampolines and 2 other fixes to have kernel
support for loading trampoline programs in bcc/bpftrace.
Original rfc post [1].
Speedup output of perf bench while running klockstat.py
on kprobes vs trampolines:
Without:
$ perf bench sched messaging -l 50000
...
Total time: 18.571 [sec]
With current kprobe tracing:
$ perf bench sched messaging -l 50000
...
Total time: 183.395 [sec]
With kfunc tracing:
$ perf bench sched messaging -l 50000
...
Total time: 39.773 [sec]
v3 changes:
- added ack from John Fastabend for patch 1
- move out is_bpf_image_address from is_bpf_text_address call [David]
v2 changes:
- make the unwind work for dispatcher as well
- added test for allowed trampolines count
- used raw tp pt_regs nest-arrays for trampoline helpers
thanks,
jirka
[1] https://lore.kernel.org/netdev/20191229143740.29143-1-jolsa@xxxxxxxxxx/
---
Jiri Olsa (6):
bpf: Allow ctx access for pointers to scalar
bpf: Add bpf_perf_event_output_kfunc
bpf: Add bpf_get_stackid_kfunc
bpf: Add bpf_get_stack_kfunc
bpf: Allow to resolve bpf trampoline and dispatcher in unwind
selftest/bpf: Add test for allowed trampolines count
include/linux/bpf.h | 12 +++++++++++-
kernel/bpf/btf.c | 13 ++++++++++++-
kernel/bpf/dispatcher.c | 4 ++--
kernel/bpf/trampoline.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
kernel/extable.c | 7 +++++--
kernel/trace/bpf_trace.c | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/prog_tests/trampoline_count.c | 112 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
tools/testing/selftests/bpf/progs/test_trampoline_count.c | 21 +++++++++++++++++++++
8 files changed, 334 insertions(+), 13 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/trampoline_count.c
create mode 100644 tools/testing/selftests/bpf/progs/test_trampoline_count.c
