From 9c42652f8be3202ad11cf4fbc358688003cff21c Mon Sep 17 00:00:00 2001 From: Hou Tao Date: Fri, 10 Dec 2021 22:16:51 +0800 Subject: selftests/bpf: Add benchmark for bpf_strncmp() helper MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add benchmark to compare the performance between home-made strncmp() in bpf program and bpf_strncmp() helper. In summary, the performance win of bpf_strncmp() under x86-64 is greater than 18% when the compared string length is greater than 64, and is 179% when the length is 4095. Under arm64 the performance win is even bigger: 33% when the length is greater than 64 and 600% when the length is 4095. The following is the details: no-helper-X: use home-made strncmp() to compare X-sized string helper-Y: use bpf_strncmp() to compare Y-sized string Under x86-64: no-helper-1 3.504 ± 0.000M/s (drops 0.000 ± 0.000M/s) helper-1 3.347 ± 0.001M/s (drops 0.000 ± 0.000M/s) no-helper-8 3.357 ± 0.001M/s (drops 0.000 ± 0.000M/s) helper-8 3.307 ± 0.001M/s (drops 0.000 ± 0.000M/s) no-helper-32 3.064 ± 0.000M/s (drops 0.000 ± 0.000M/s) helper-32 3.253 ± 0.001M/s (drops 0.000 ± 0.000M/s) no-helper-64 2.563 ± 0.001M/s (drops 0.000 ± 0.000M/s) helper-64 3.040 ± 0.001M/s (drops 0.000 ± 0.000M/s) no-helper-128 1.975 ± 0.000M/s (drops 0.000 ± 0.000M/s) helper-128 2.641 ± 0.000M/s (drops 0.000 ± 0.000M/s) no-helper-512 0.759 ± 0.000M/s (drops 0.000 ± 0.000M/s) helper-512 1.574 ± 0.000M/s (drops 0.000 ± 0.000M/s) no-helper-2048 0.329 ± 0.000M/s (drops 0.000 ± 0.000M/s) helper-2048 0.602 ± 0.000M/s (drops 0.000 ± 0.000M/s) no-helper-4095 0.117 ± 0.000M/s (drops 0.000 ± 0.000M/s) helper-4095 0.327 ± 0.000M/s (drops 0.000 ± 0.000M/s) Under arm64: no-helper-1 2.806 ± 0.004M/s (drops 0.000 ± 0.000M/s) helper-1 2.819 ± 0.002M/s (drops 0.000 ± 0.000M/s) no-helper-8 2.797 ± 0.109M/s (drops 0.000 ± 0.000M/s) helper-8 2.786 ± 0.025M/s (drops 0.000 ± 0.000M/s) no-helper-32 2.399 ± 0.011M/s (drops 0.000 ± 0.000M/s) helper-32 2.703 ± 0.002M/s (drops 0.000 ± 0.000M/s) no-helper-64 2.020 ± 0.015M/s (drops 0.000 ± 0.000M/s) helper-64 2.702 ± 0.073M/s (drops 0.000 ± 0.000M/s) no-helper-128 1.604 ± 0.001M/s (drops 0.000 ± 0.000M/s) helper-128 2.516 ± 0.002M/s (drops 0.000 ± 0.000M/s) no-helper-512 0.699 ± 0.000M/s (drops 0.000 ± 0.000M/s) helper-512 2.106 ± 0.003M/s (drops 0.000 ± 0.000M/s) no-helper-2048 0.215 ± 0.000M/s (drops 0.000 ± 0.000M/s) helper-2048 1.223 ± 0.003M/s (drops 0.000 ± 0.000M/s) no-helper-4095 0.112 ± 0.000M/s (drops 0.000 ± 0.000M/s) helper-4095 0.796 ± 0.000M/s (drops 0.000 ± 0.000M/s) Signed-off-by: Hou Tao Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20211210141652.877186-4-houtao1@huawei.com --- tools/testing/selftests/bpf/Makefile | 4 +- tools/testing/selftests/bpf/bench.c | 6 + tools/testing/selftests/bpf/benchs/bench_strncmp.c | 161 +++++++++++++++++++++ .../selftests/bpf/benchs/run_bench_strncmp.sh | 12 ++ tools/testing/selftests/bpf/progs/strncmp_bench.c | 50 +++++++ 5 files changed, 232 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/benchs/bench_strncmp.c create mode 100755 tools/testing/selftests/bpf/benchs/run_bench_strncmp.sh create mode 100644 tools/testing/selftests/bpf/progs/strncmp_bench.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index a795bca4c8ec..43f6f3159431 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -537,6 +537,7 @@ $(OUTPUT)/bench_ringbufs.o: $(OUTPUT)/ringbuf_bench.skel.h \ $(OUTPUT)/perfbuf_bench.skel.h $(OUTPUT)/bench_bloom_filter_map.o: $(OUTPUT)/bloom_filter_bench.skel.h $(OUTPUT)/bench_bpf_loop.o: $(OUTPUT)/bpf_loop_bench.skel.h +$(OUTPUT)/bench_strncmp.o: $(OUTPUT)/strncmp_bench.skel.h $(OUTPUT)/bench.o: bench.h testing_helpers.h $(BPFOBJ) $(OUTPUT)/bench: LDLIBS += -lm $(OUTPUT)/bench: $(OUTPUT)/bench.o \ @@ -547,7 +548,8 @@ $(OUTPUT)/bench: $(OUTPUT)/bench.o \ $(OUTPUT)/bench_trigger.o \ $(OUTPUT)/bench_ringbufs.o \ $(OUTPUT)/bench_bloom_filter_map.o \ - $(OUTPUT)/bench_bpf_loop.o + $(OUTPUT)/bench_bpf_loop.o \ + $(OUTPUT)/bench_strncmp.o $(call msg,BINARY,,$@) $(Q)$(CC) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@ diff --git a/tools/testing/selftests/bpf/bench.c b/tools/testing/selftests/bpf/bench.c index ffe5752f3324..bbb42e2cee0c 100644 --- a/tools/testing/selftests/bpf/bench.c +++ b/tools/testing/selftests/bpf/bench.c @@ -205,11 +205,13 @@ static const struct argp_option opts[] = { extern struct argp bench_ringbufs_argp; extern struct argp bench_bloom_map_argp; extern struct argp bench_bpf_loop_argp; +extern struct argp bench_strncmp_argp; static const struct argp_child bench_parsers[] = { { &bench_ringbufs_argp, 0, "Ring buffers benchmark", 0 }, { &bench_bloom_map_argp, 0, "Bloom filter map benchmark", 0 }, { &bench_bpf_loop_argp, 0, "bpf_loop helper benchmark", 0 }, + { &bench_strncmp_argp, 0, "bpf_strncmp helper benchmark", 0 }, {}, }; @@ -409,6 +411,8 @@ extern const struct bench bench_bloom_false_positive; extern const struct bench bench_hashmap_without_bloom; extern const struct bench bench_hashmap_with_bloom; extern const struct bench bench_bpf_loop; +extern const struct bench bench_strncmp_no_helper; +extern const struct bench bench_strncmp_helper; static const struct bench *benchs[] = { &bench_count_global, @@ -441,6 +445,8 @@ static const struct bench *benchs[] = { &bench_hashmap_without_bloom, &bench_hashmap_with_bloom, &bench_bpf_loop, + &bench_strncmp_no_helper, + &bench_strncmp_helper, }; static void setup_benchmark() diff --git a/tools/testing/selftests/bpf/benchs/bench_strncmp.c b/tools/testing/selftests/bpf/benchs/bench_strncmp.c new file mode 100644 index 000000000000..494b591c0289 --- /dev/null +++ b/tools/testing/selftests/bpf/benchs/bench_strncmp.c @@ -0,0 +1,161 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2021. Huawei Technologies Co., Ltd */ +#include +#include "bench.h" +#include "strncmp_bench.skel.h" + +static struct strncmp_ctx { + struct strncmp_bench *skel; +} ctx; + +static struct strncmp_args { + u32 cmp_str_len; +} args = { + .cmp_str_len = 32, +}; + +enum { + ARG_CMP_STR_LEN = 5000, +}; + +static const struct argp_option opts[] = { + { "cmp-str-len", ARG_CMP_STR_LEN, "CMP_STR_LEN", 0, + "Set the length of compared string" }, + {}, +}; + +static error_t strncmp_parse_arg(int key, char *arg, struct argp_state *state) +{ + switch (key) { + case ARG_CMP_STR_LEN: + args.cmp_str_len = strtoul(arg, NULL, 10); + if (!args.cmp_str_len || + args.cmp_str_len >= sizeof(ctx.skel->bss->str)) { + fprintf(stderr, "Invalid cmp str len (limit %zu)\n", + sizeof(ctx.skel->bss->str)); + argp_usage(state); + } + break; + default: + return ARGP_ERR_UNKNOWN; + } + + return 0; +} + +const struct argp bench_strncmp_argp = { + .options = opts, + .parser = strncmp_parse_arg, +}; + +static void strncmp_validate(void) +{ + if (env.consumer_cnt != 1) { + fprintf(stderr, "strncmp benchmark doesn't support multi-consumer!\n"); + exit(1); + } +} + +static void strncmp_setup(void) +{ + int err; + char *target; + size_t i, sz; + + sz = sizeof(ctx.skel->rodata->target); + if (!sz || sz < sizeof(ctx.skel->bss->str)) { + fprintf(stderr, "invalid string size (target %zu, src %zu)\n", + sz, sizeof(ctx.skel->bss->str)); + exit(1); + } + + setup_libbpf(); + + ctx.skel = strncmp_bench__open(); + if (!ctx.skel) { + fprintf(stderr, "failed to open skeleton\n"); + exit(1); + } + + srandom(time(NULL)); + target = ctx.skel->rodata->target; + for (i = 0; i < sz - 1; i++) + target[i] = '1' + random() % 9; + target[sz - 1] = '\0'; + + ctx.skel->rodata->cmp_str_len = args.cmp_str_len; + + memcpy(ctx.skel->bss->str, target, args.cmp_str_len); + ctx.skel->bss->str[args.cmp_str_len] = '\0'; + /* Make bss->str < rodata->target */ + ctx.skel->bss->str[args.cmp_str_len - 1] -= 1; + + err = strncmp_bench__load(ctx.skel); + if (err) { + fprintf(stderr, "failed to load skeleton\n"); + strncmp_bench__destroy(ctx.skel); + exit(1); + } +} + +static void strncmp_attach_prog(struct bpf_program *prog) +{ + struct bpf_link *link; + + link = bpf_program__attach(prog); + if (!link) { + fprintf(stderr, "failed to attach program!\n"); + exit(1); + } +} + +static void strncmp_no_helper_setup(void) +{ + strncmp_setup(); + strncmp_attach_prog(ctx.skel->progs.strncmp_no_helper); +} + +static void strncmp_helper_setup(void) +{ + strncmp_setup(); + strncmp_attach_prog(ctx.skel->progs.strncmp_helper); +} + +static void *strncmp_producer(void *ctx) +{ + while (true) + (void)syscall(__NR_getpgid); + return NULL; +} + +static void *strncmp_consumer(void *ctx) +{ + return NULL; +} + +static void strncmp_measure(struct bench_res *res) +{ + res->hits = atomic_swap(&ctx.skel->bss->hits, 0); +} + +const struct bench bench_strncmp_no_helper = { + .name = "strncmp-no-helper", + .validate = strncmp_validate, + .setup = strncmp_no_helper_setup, + .producer_thread = strncmp_producer, + .consumer_thread = strncmp_consumer, + .measure = strncmp_measure, + .report_progress = hits_drops_report_progress, + .report_final = hits_drops_report_final, +}; + +const struct bench bench_strncmp_helper = { + .name = "strncmp-helper", + .validate = strncmp_validate, + .setup = strncmp_helper_setup, + .producer_thread = strncmp_producer, + .consumer_thread = strncmp_consumer, + .measure = strncmp_measure, + .report_progress = hits_drops_report_progress, + .report_final = hits_drops_report_final, +}; diff --git a/tools/testing/selftests/bpf/benchs/run_bench_strncmp.sh b/tools/testing/selftests/bpf/benchs/run_bench_strncmp.sh new file mode 100755 index 000000000000..142697284b45 --- /dev/null +++ b/tools/testing/selftests/bpf/benchs/run_bench_strncmp.sh @@ -0,0 +1,12 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +source ./benchs/run_common.sh + +set -eufo pipefail + +for s in 1 8 64 512 2048 4095; do + for b in no-helper helper; do + summarize ${b}-${s} "$($RUN_BENCH --cmp-str-len=$s strncmp-${b})" + done +done diff --git a/tools/testing/selftests/bpf/progs/strncmp_bench.c b/tools/testing/selftests/bpf/progs/strncmp_bench.c new file mode 100644 index 000000000000..18373a7df76e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/strncmp_bench.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2021. Huawei Technologies Co., Ltd */ +#include +#include +#include +#include + +#define STRNCMP_STR_SZ 4096 + +/* Will be updated by benchmark before program loading */ +const volatile unsigned int cmp_str_len = 1; +const char target[STRNCMP_STR_SZ]; + +long hits = 0; +char str[STRNCMP_STR_SZ]; + +char _license[] SEC("license") = "GPL"; + +static __always_inline int local_strncmp(const char *s1, unsigned int sz, + const char *s2) +{ + int ret = 0; + unsigned int i; + + for (i = 0; i < sz; i++) { + /* E.g. 0xff > 0x31 */ + ret = (unsigned char)s1[i] - (unsigned char)s2[i]; + if (ret || !s1[i]) + break; + } + + return ret; +} + +SEC("tp/syscalls/sys_enter_getpgid") +int strncmp_no_helper(void *ctx) +{ + if (local_strncmp(str, cmp_str_len + 1, target) < 0) + __sync_add_and_fetch(&hits, 1); + return 0; +} + +SEC("tp/syscalls/sys_enter_getpgid") +int strncmp_helper(void *ctx) +{ + if (bpf_strncmp(str, cmp_str_len + 1, target) < 0) + __sync_add_and_fetch(&hits, 1); + return 0; +} + -- cgit v1.2.3