On Mon, Nov 29, 2021 at 2:39 PM Joanne Koong <joannekoong@xxxxxx> wrote:
>
> This patch tests bpf_loop in pyperf and strobemeta, and measures the
> verifier performance of replacing the traditional for loop
> with bpf_loop.
>
> The results are as follows:
>
> ~strobemeta~
>
> Baseline
> verification time 6808200 usec
> stack depth 496
> processed 554252 insns (limit 1000000) max_states_per_insn 16
> total_states 15878 peak_states 13489 mark_read 3110
> #192 verif_scale_strobemeta:OK (unrolled loop)
>
> Using bpf_loop
> verification time 31589 usec
> stack depth 96+400
> processed 1513 insns (limit 1000000) max_states_per_insn 2
> total_states 106 peak_states 106 mark_read 60
> #193 verif_scale_strobemeta_bpf_loop:OK
>
> ~pyperf600~
>
> Baseline
> verification time 29702486 usec
> stack depth 368
> processed 626838 insns (limit 1000000) max_states_per_insn 7
> total_states 30368 peak_states 30279 mark_read 748
> #182 verif_scale_pyperf600:OK (unrolled loop)
>
> Using bpf_loop
> verification time 148488 usec
> stack depth 320+40
> processed 10518 insns (limit 1000000) max_states_per_insn 10
> total_states 705 peak_states 517 mark_read 38
> #183 verif_scale_pyperf600_bpf_loop:OK
>
> Using the bpf_loop helper led to approximately a 99% decrease
> in the verification time and in the number of instructions.
>
> Signed-off-by: Joanne Koong <joannekoong@xxxxxx>
> ---
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> .../bpf/prog_tests/bpf_verif_scale.c | 12 +++
> tools/testing/selftests/bpf/progs/pyperf.h | 71 +++++++++++++++++-
> .../selftests/bpf/progs/pyperf600_bpf_loop.c | 6 ++
> .../testing/selftests/bpf/progs/strobemeta.h | 75 ++++++++++++++++++-
> .../selftests/bpf/progs/strobemeta_bpf_loop.c | 9 +++
> 5 files changed, 169 insertions(+), 4 deletions(-)
> create mode 100644 tools/testing/selftests/bpf/progs/pyperf600_bpf_loop.c
> create mode 100644 tools/testing/selftests/bpf/progs/strobemeta_bpf_loop.c
>
[...]
> /* Unwind python stack */
> for (int i = 0; i < STACK_MAX_LEN; ++i) {
> if (frame_ptr && get_frame_data(frame_ptr, pidData, &frame, &sym)) {
> @@ -251,6 +319,7 @@ int __on_event(struct bpf_raw_tracepoint_args *ctx)
> frame_ptr = frame.f_back;
> }
> }
> +#endif /* USE_BPF_LOOP */
> event->stack_complete = frame_ptr == NULL;
> } else {
> event->stack_complete = 1;
> diff --git a/tools/testing/selftests/bpf/progs/pyperf600_bpf_loop.c b/tools/testing/selftests/bpf/progs/pyperf600_bpf_loop.c
> new file mode 100644
> index 000000000000..bde8baed4ca6
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/pyperf600_bpf_loop.c
> @@ -0,0 +1,6 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2021 Facebook
nit: should be /* ... */
> +
> +#define STACK_MAX_LEN 600
> +#define USE_BPF_LOOP
> +#include "pyperf.h"
[...]
> diff --git a/tools/testing/selftests/bpf/progs/strobemeta_bpf_loop.c b/tools/testing/selftests/bpf/progs/strobemeta_bpf_loop.c
> new file mode 100644
> index 000000000000..e6f9f920e68a
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/strobemeta_bpf_loop.c
> @@ -0,0 +1,9 @@
> +// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
> +// Copyright (c) 2021 Facebook
same
> +
> +#define STROBE_MAX_INTS 2
> +#define STROBE_MAX_STRS 25
> +#define STROBE_MAX_MAPS 100
> +#define STROBE_MAX_MAP_ENTRIES 20
> +#define USE_BPF_LOOP
> +#include "strobemeta.h"
> --
> 2.30.2
>
