selftests/bpf/benchs: Add overwrite mode benchmark for BPF ring buffer (f9db3a38) · Commits · git / linux-net

tools/testing/selftests/bpf/benchs/bench_ringbufs.c

+59 −6

Original line number	Diff line number	Diff line
		@@ -19,6 +19,8 @@ static struct {
		int ringbuf_sz; /* per-ringbuf, in bytes */
		bool ringbuf_use_output; /* use slower output API */
		int perfbuf_sz; /* per-CPU size, in pages */
		bool overwrite;
		bool bench_producer;
		} args = {
		.back2back = false,
		.batch_cnt = 500,
		@@ -27,6 +29,8 @@ static struct {
		.ringbuf_sz = 512 * 1024,
		.ringbuf_use_output = false,
		.perfbuf_sz = 128,
		.overwrite = false,
		.bench_producer = false,
		};

		enum {
		@@ -35,6 +39,8 @@ enum {
		ARG_RB_BATCH_CNT = 2002,
		ARG_RB_SAMPLED = 2003,
		ARG_RB_SAMPLE_RATE = 2004,
		ARG_RB_OVERWRITE = 2005,
		ARG_RB_BENCH_PRODUCER = 2006,
		};

		static const struct argp_option opts[] = {
		@@ -43,6 +49,8 @@ static const struct argp_option opts[] = {
		{ "rb-batch-cnt", ARG_RB_BATCH_CNT, "CNT", 0, "Set BPF-side record batch count"},
		{ "rb-sampled", ARG_RB_SAMPLED, NULL, 0, "Notification sampling"},
		{ "rb-sample-rate", ARG_RB_SAMPLE_RATE, "RATE", 0, "Notification sample rate"},
		{ "rb-overwrite", ARG_RB_OVERWRITE, NULL, 0, "Overwrite mode"},
		{ "rb-bench-producer", ARG_RB_BENCH_PRODUCER, NULL, 0, "Benchmark producer"},
		{},
		};

		@@ -72,6 +80,12 @@ static error_t parse_arg(int key, char arg, struct argp_state state)
		argp_usage(state);
		}
		break;
		case ARG_RB_OVERWRITE:
		args.overwrite = true;
		break;
		case ARG_RB_BENCH_PRODUCER:
		args.bench_producer = true;
		break;
		default:
		return ARGP_ERR_UNKNOWN;
		}
		@@ -95,8 +109,33 @@ static inline void bufs_trigger_batch(void)

		static void bufs_validate(void)
		{
		if (env.consumer_cnt != 1) {
		fprintf(stderr, "rb-libbpf benchmark needs one consumer!\n");
		if (args.bench_producer && strcmp(env.bench_name, "rb-libbpf")) {
		fprintf(stderr, "--rb-bench-producer only works with rb-libbpf!\n");
		exit(1);
		}

		if (args.overwrite && !args.bench_producer) {
		fprintf(stderr, "overwrite mode only works with --rb-bench-producer for now!\n");
		exit(1);
		}

		if (args.bench_producer && env.consumer_cnt != 0) {
		fprintf(stderr, "no consumer is needed for --rb-bench-producer!\n");
		exit(1);
		}

		if (args.bench_producer && args.back2back) {
		fprintf(stderr, "back-to-back mode makes no sense for --rb-bench-producer!\n");
		exit(1);
		}

		if (args.bench_producer && args.sampled) {
		fprintf(stderr, "sampling mode makes no sense for --rb-bench-producer!\n");
		exit(1);
		}

		if (!args.bench_producer && env.consumer_cnt != 1) {
		fprintf(stderr, "benchmarks without --rb-bench-producer require exactly one consumer!\n");
		exit(1);
		}

		@@ -128,12 +167,17 @@ static void ringbuf_libbpf_measure(struct bench_res *res)
		{
		struct ringbuf_libbpf_ctx *ctx = &ringbuf_libbpf_ctx;

		if (args.bench_producer)
		res->hits = atomic_swap(&ctx->skel->bss->hits, 0);
		else
		res->hits = atomic_swap(&buf_hits.value, 0);
		res->drops = atomic_swap(&ctx->skel->bss->dropped, 0);
		}

		static struct ringbuf_bench *ringbuf_setup_skeleton(void)
		{
		__u32 flags;
		struct bpf_map *ringbuf;
		struct ringbuf_bench *skel;

		setup_libbpf();
		@@ -146,12 +190,19 @@ static struct ringbuf_bench *ringbuf_setup_skeleton(void)

		skel->rodata->batch_cnt = args.batch_cnt;
		skel->rodata->use_output = args.ringbuf_use_output ? 1 : 0;
		skel->rodata->bench_producer = args.bench_producer;

		if (args.sampled)
		/* record data + header take 16 bytes */
		skel->rodata->wakeup_data_size = args.sample_rate * 16;

		bpf_map__set_max_entries(skel->maps.ringbuf, args.ringbuf_sz);
		ringbuf = skel->maps.ringbuf;
		if (args.overwrite) {
		flags = bpf_map__map_flags(ringbuf) \| BPF_F_RB_OVERWRITE;
		bpf_map__set_map_flags(ringbuf, flags);
		}

		bpf_map__set_max_entries(ringbuf, args.ringbuf_sz);

		if (ringbuf_bench__load(skel)) {
		fprintf(stderr, "failed to load skeleton\n");
		@@ -171,10 +222,12 @@ static void ringbuf_libbpf_setup(void)
		{
		struct ringbuf_libbpf_ctx *ctx = &ringbuf_libbpf_ctx;
		struct bpf_link *link;
		int map_fd;

		ctx->skel = ringbuf_setup_skeleton();
		ctx->ringbuf = ring_buffer__new(bpf_map__fd(ctx->skel->maps.ringbuf),
		buf_process_sample, NULL, NULL);

		map_fd = bpf_map__fd(ctx->skel->maps.ringbuf);
		ctx->ringbuf = ring_buffer__new(map_fd, buf_process_sample, NULL, NULL);
		if (!ctx->ringbuf) {
		fprintf(stderr, "failed to create ringbuf\n");
		exit(1);

tools/testing/selftests/bpf/benchs/run_bench_ringbufs.sh

+4 −0

Original line number	Diff line number	Diff line
		@@ -49,3 +49,7 @@ for b in 1 2 3 4 8 12 16 20 24 28 32 36 40 44 48 52; do
		summarize "rb-libbpf nr_prod $b" "$($RUN_RB_BENCH -p$b --rb-batch-cnt 50 rb-libbpf)"
		done

		header "Ringbuf, multi-producer contention in overwrite mode, no consumer"
		for b in 1 2 3 4 8 12 16 20 24 28 32 36 40 44 48 52; do
		summarize "rb-prod nr_prod $b" "$($RUN_BENCH -p$b --rb-batch-cnt 50 --rb-overwrite --rb-bench-producer rb-libbpf)"
		done

tools/testing/selftests/bpf/progs/ringbuf_bench.c

+11 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		// Copyright (c) 2020 Facebook

		#include <stdbool.h>
		#include <linux/bpf.h>
		#include <stdint.h>
		#include <bpf/bpf_helpers.h>
		@@ -14,9 +15,11 @@ struct {

		const volatile int batch_cnt = 0;
		const volatile long use_output = 0;
		const volatile bool bench_producer = false;

		long sample_val = 42;
		long dropped __attribute__((aligned(128))) = 0;
		long hits __attribute__((aligned(128))) = 0;

		const volatile long wakeup_data_size = 0;

		@@ -24,6 +27,9 @@ static __always_inline long get_flags()
		{
		long sz;

		if (bench_producer)
		return BPF_RB_NO_WAKEUP;

		if (!wakeup_data_size)
		return 0;

		@@ -47,6 +53,8 @@ int bench_ringbuf(void *ctx)
		*sample = sample_val;
		flags = get_flags();
		bpf_ringbuf_submit(sample, flags);
		if (bench_producer)
		__sync_add_and_fetch(&hits, 1);
		}
		}
		} else {
		@@ -55,6 +63,9 @@ int bench_ringbuf(void *ctx)
		if (bpf_ringbuf_output(&ringbuf, &sample_val,
		sizeof(sample_val), flags))
		__sync_add_and_fetch(&dropped, 1);
		else if (bench_producer)
		__sync_add_and_fetch(&hits, 1);

		}
		}
		return 0;