On 5/8/20 4:20 PM, Andrii Nakryiko wrote:
Add fmod_ret BPF program to existing test_overhead selftest. Also re-implement user-space benchmarking part into benchmark runner to compare results. Results with ./bench are consistently somewhat lower than test_overhead's, but relative performance of various types of BPF programs stay consisten (e.g., kretprobe is noticeably slower). run_bench_rename.sh script (in benchs/ directory) was used to produce the following numbers: base : 3.975 ± 0.065M/s kprobe : 3.268 ± 0.095M/s kretprobe : 2.496 ± 0.040M/s rawtp : 3.899 ± 0.078M/s fentry : 3.836 ± 0.049M/s fexit : 3.660 ± 0.082M/s fmodret : 3.776 ± 0.033M/s While running test_overhead gives: task_rename base 4457K events per sec task_rename kprobe 3849K events per sec task_rename kretprobe 2729K events per sec task_rename raw_tp 4506K events per sec task_rename fentry 4381K events per sec task_rename fexit 4349K events per sec task_rename fmod_ret 4130K events per sec
Do you where the overhead is and how we could provide options in bench to reduce the overhead so we can achieve similar numbers? For benchmarking, sometimes you really want to see "true" potential of a particular implementation.
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx> Signed-off-by: Andrii Nakryiko <andriin@xxxxxx> --- tools/testing/selftests/bpf/Makefile | 4 +- tools/testing/selftests/bpf/bench.c | 14 ++ .../selftests/bpf/benchs/bench_rename.c | 195 ++++++++++++++++++ .../selftests/bpf/benchs/run_bench_rename.sh | 9 + .../selftests/bpf/prog_tests/test_overhead.c | 14 +- .../selftests/bpf/progs/test_overhead.c | 6 + 6 files changed, 240 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/benchs/bench_rename.c create mode 100755 tools/testing/selftests/bpf/benchs/run_bench_rename.sh diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 289fffbf975e..29a02abf81a3 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -409,10 +409,12 @@ $(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ) $(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h $(call msg,CC,,$@) $(CC) $(CFLAGS) -c $(filter %.c,$^) $(LDLIBS) -o $@ +$(OUTPUT)/bench_rename.o: $(OUTPUT)/test_overhead.skel.h $(OUTPUT)/bench.o: bench.h $(OUTPUT)/bench: LDLIBS += -lm $(OUTPUT)/bench: $(OUTPUT)/bench.o \ - $(OUTPUT)/bench_count.o + $(OUTPUT)/bench_count.o \ + $(OUTPUT)/bench_rename.o $(call msg,BINARY,,$@) $(CC) $(LDFLAGS) -o $@ $(filter %.a %.o,$^) $(LDLIBS)
[...]
