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| author |   Andrii Nakryiko <andrii@kernel.org> | 2021-11-15 17:30:41 -0800 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2021-11-16 14:46:49 +0100 |
| commit | d41bc48bfab2076f7db88d079a3a3203dd9c4a54 (patch) | |
| tree | a498bb26f6d16d4e00cada646a8fe6fd1f6687f4 /tools/testing/selftests/bpf/bench.c | |
| parent | bpf: Change value of MAX_TAIL_CALL_CNT from 32 to 33 (diff) | |
| download | linux-dev-d41bc48bfab2076f7db88d079a3a3203dd9c4a54.tar.xz linux-dev-d41bc48bfab2076f7db88d079a3a3203dd9c4a54.zip | |
selftests/bpf: Add uprobe triggering overhead benchmarks
Add benchmark to measure overhead of uprobes and uretprobes. Also have
a baseline (no uprobe attached) benchmark.
On my dev machine, baseline benchmark can trigger 130M user_target()
invocations. When uprobe is attached, this falls to just 700K. With
uretprobe, we get down to 520K:
$ sudo ./bench trig-uprobe-base -a
Summary: hits 131.289 ± 2.872M/s
# UPROBE
$ sudo ./bench -a trig-uprobe-without-nop
Summary: hits 0.729 ± 0.007M/s
$ sudo ./bench -a trig-uprobe-with-nop
Summary: hits 1.798 ± 0.017M/s
# URETPROBE
$ sudo ./bench -a trig-uretprobe-without-nop
Summary: hits 0.508 ± 0.012M/s
$ sudo ./bench -a trig-uretprobe-with-nop
Summary: hits 0.883 ± 0.008M/s
So there is almost 2.5x performance difference between probing nop vs
non-nop instruction for entry uprobe. And 1.7x difference for uretprobe.
This means that non-nop uprobe overhead is around 1.4 microseconds for uprobe
and 2 microseconds for non-nop uretprobe.
For nop variants, uprobe and uretprobe overhead is down to 0.556 and
1.13 microseconds, respectively.
For comparison, just doing a very low-overhead syscall (with no BPF
programs attached anywhere) gives:
$ sudo ./bench trig-base -a
Summary: hits 4.830 ± 0.036M/s
So uprobes are about 2.67x slower than pure context switch.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211116013041.4072571-1-andrii@kernel.org
Diffstat (limited to 'tools/testing/selftests/bpf/bench.c')
| -rw-r--r-- | tools/testing/selftests/bpf/bench.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/bench.c b/tools/testing/selftests/bpf/bench.c index cc4722f693e9..c75e7ee28746 100644 --- a/tools/testing/selftests/bpf/bench.c +++ b/tools/testing/selftests/bpf/bench.c @@ -359,6 +359,11 @@ extern const struct bench bench_trig_kprobe; extern const struct bench bench_trig_fentry; extern const struct bench bench_trig_fentry_sleep; extern const struct bench bench_trig_fmodret; +extern const struct bench bench_trig_uprobe_base; +extern const struct bench bench_trig_uprobe_with_nop; +extern const struct bench bench_trig_uretprobe_with_nop; +extern const struct bench bench_trig_uprobe_without_nop; +extern const struct bench bench_trig_uretprobe_without_nop; extern const struct bench bench_rb_libbpf; extern const struct bench bench_rb_custom; extern const struct bench bench_pb_libbpf; @@ -385,6 +390,11 @@ static const struct bench *benchs[] = { &bench_trig_fentry, &bench_trig_fentry_sleep, &bench_trig_fmodret, + &bench_trig_uprobe_base, + &bench_trig_uprobe_with_nop, + &bench_trig_uretprobe_with_nop, + &bench_trig_uprobe_without_nop, + &bench_trig_uretprobe_without_nop, &bench_rb_libbpf, &bench_rb_custom, &bench_pb_libbpf, |