On Fri, May 31, 2019 at 11:39:52PM -0700, Andrii Nakryiko wrote:
> This patch adds a new test program, based on real-world production
> application, for testing BPF verifier scalability w/ realistic
> complexity.
Thanks!
> - const char *pyperf[] = {
> + const char *tp_progs[] = {
I had very similar change in my repo :)
> +struct strobemeta_payload {
> + /* req_id has valid request ID, if req_meta_valid == 1 */
> + int64_t req_id;
> + uint8_t req_meta_valid;
> + /*
> + * mask has Nth bit set to 1, if Nth metavar was present and
> + * successfully read
> + */
> + uint64_t int_vals_set_mask;
> + int64_t int_vals[STROBE_MAX_INTS];
> + /* len is >0 for present values */
> + uint16_t str_lens[STROBE_MAX_STRS];
> + /* if map_descrs[i].cnt == -1, metavar is not present/set */
> + struct strobe_map_descr map_descrs[STROBE_MAX_MAPS];
> + /*
> + * payload has compactly packed values of str and map variables in the
> + * form: strval1\0strval2\0map1key1\0map1val1\0map2key1\0map2val1\0
> + * (and so on); str_lens[i], key_lens[i] and val_lens[i] determines
> + * value length
> + */
> + char payload[STROBE_MAX_PAYLOAD];
> +};
> +
> +struct strobelight_bpf_sample {
> + uint64_t ktime;
> + char comm[TASK_COMM_LEN];
> + pid_t pid;
> + int user_stack_id;
> + int kernel_stack_id;
> + int has_meta;
> + struct strobemeta_payload metadata;
> + /*
> + * makes it possible to pass (<real payload size> + 1) as data size to
> + * perf_submit() to avoid perf_submit's paranoia about passing zero as
> + * size, as it deduces that <real payload size> might be
> + * **theoretically** zero
> + */
> + char dummy_safeguard;
> +};
> +struct bpf_map_def SEC("maps") sample_heap = {
> + .type = BPF_MAP_TYPE_PERCPU_ARRAY,
> + .key_size = sizeof(uint32_t),
> + .value_size = sizeof(struct strobelight_bpf_sample),
> + .max_entries = 1,
> +};
due to this design the stressfulness of the test is
limited by bpf max map value limitation which comes from
alloc_percpu limit.
That makes it not as stressful as I was hoping for :)
> +#define STROBE_MAX_INTS 25
> +#define STROBE_MAX_STRS 25
> +#define STROBE_MAX_MAPS 5
> +#define STROBE_MAX_MAP_ENTRIES 20
so I could bump STROBE_MAX_INTS to 300 and got:
verification time 302401 usec // with kasan
stack depth 464
processed 40388 insns (limit 1000000) max_states_per_insn 6 total_states 8863 peak_states 8796 mark_read 4110
test_scale:./strobemeta25.o:OK
which is not that stressful comparing to some of the tests :)
Without unroll:
verification time 435963 usec // with kasan
stack depth 488
processed 52812 insns (limit 1000000) max_states_per_insn 26 total_states 6786 peak_states 1405 mark_read 777
test_scale:./strobemeta25.o:OK
So things are looking pretty good.
I'll roll your test into my set with few tweaks. Thanks a lot!
btw I consistently see better code and less insn_processed in alu32 mode.
It's probably time to make it llvm default.
