Add benchmark to measure the throughput and latency of the bpf_loop
call.
Testing this on my dev machine on 1 thread, the data is as follows:
nr_loops: 10
bpf_loop - throughput: 198.519 ± 0.155 M ops/s, latency: 5.037 ns/op
nr_loops: 100
bpf_loop - throughput: 247.448 ± 0.305 M ops/s, latency: 4.041 ns/op
nr_loops: 500
bpf_loop - throughput: 260.839 ± 0.380 M ops/s, latency: 3.834 ns/op
nr_loops: 1000
bpf_loop - throughput: 262.806 ± 0.629 M ops/s, latency: 3.805 ns/op
nr_loops: 5000
bpf_loop - throughput: 264.211 ± 1.508 M ops/s, latency: 3.785 ns/op
nr_loops: 10000
bpf_loop - throughput: 265.366 ± 3.054 M ops/s, latency: 3.768 ns/op
nr_loops: 50000
bpf_loop - throughput: 235.986 ± 20.205 M ops/s, latency: 4.238 ns/op
nr_loops: 100000
bpf_loop - throughput: 264.482 ± 0.279 M ops/s, latency: 3.781 ns/op
nr_loops: 500000
bpf_loop - throughput: 309.773 ± 87.713 M ops/s, latency: 3.228 ns/op
nr_loops:
1000000
bpf_loop - throughput: 262.818 ± 4.143 M ops/s, latency: 3.805 ns/op
>From this data, we can see that the latency per loop decreases as the
number of loops increases. On this particular machine, each loop had an
overhead of about ~4 ns, and we were able to run ~250 million loops
per second.
Signed-off-by: Joanne Koong <joannekoong@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211130030622.4131246-5-joannekoong@fb.com
$(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.o: bench.h testing_helpers.h $(BPFOBJ)
$(OUTPUT)/bench: LDLIBS += -lm
$(OUTPUT)/bench: $(OUTPUT)/bench.o \
$(OUTPUT)/bench_rename.o \
$(OUTPUT)/bench_trigger.o \
$(OUTPUT)/bench_ringbufs.o \
- $(OUTPUT)/bench_bloom_filter_map.o
+ $(OUTPUT)/bench_bloom_filter_map.o \
+ $(OUTPUT)/bench_bpf_loop.o
$(call msg,BINARY,,$@)
$(Q)$(CC) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@
total_ops_mean, total_ops_stddev);
}
+void ops_report_progress(int iter, struct bench_res *res, long delta_ns)
+{
+ double hits_per_sec, hits_per_prod;
+
+ hits_per_sec = res->hits / 1000000.0 / (delta_ns / 1000000000.0);
+ hits_per_prod = hits_per_sec / env.producer_cnt;
+
+ printf("Iter %3d (%7.3lfus): ", iter, (delta_ns - 1000000000) / 1000.0);
+
+ printf("hits %8.3lfM/s (%7.3lfM/prod)\n", hits_per_sec, hits_per_prod);
+}
+
+void ops_report_final(struct bench_res res[], int res_cnt)
+{
+ double hits_mean = 0.0, hits_stddev = 0.0;
+ int i;
+
+ for (i = 0; i < res_cnt; i++)
+ hits_mean += res[i].hits / 1000000.0 / (0.0 + res_cnt);
+
+ if (res_cnt > 1) {
+ for (i = 0; i < res_cnt; i++)
+ hits_stddev += (hits_mean - res[i].hits / 1000000.0) *
+ (hits_mean - res[i].hits / 1000000.0) /
+ (res_cnt - 1.0);
+
+ hits_stddev = sqrt(hits_stddev);
+ }
+ printf("Summary: throughput %8.3lf \u00B1 %5.3lf M ops/s (%7.3lfM ops/prod), ",
+ hits_mean, hits_stddev, hits_mean / env.producer_cnt);
+ printf("latency %8.3lf ns/op\n", 1000.0 / hits_mean * env.producer_cnt);
+}
+
const char *argp_program_version = "benchmark";
const char *argp_program_bug_address = "<bpf@vger.kernel.org>";
const char argp_program_doc[] =
extern struct argp bench_ringbufs_argp;
extern struct argp bench_bloom_map_argp;
+extern struct argp bench_bpf_loop_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 },
{},
};
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;
static const struct bench *benchs[] = {
&bench_count_global,
&bench_bloom_false_positive,
&bench_hashmap_without_bloom,
&bench_hashmap_with_bloom,
+ &bench_bpf_loop,
};
static void setup_benchmark()
void hits_drops_report_final(struct bench_res res[], int res_cnt);
void false_hits_report_progress(int iter, struct bench_res *res, long delta_ns);
void false_hits_report_final(struct bench_res res[], int res_cnt);
+void ops_report_progress(int iter, struct bench_res *res, long delta_ns);
+void ops_report_final(struct bench_res res[], int res_cnt);
static inline __u64 get_time_ns() {
struct timespec t;
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+
+#include <argp.h>
+#include "bench.h"
+#include "bpf_loop_bench.skel.h"
+
+/* BPF triggering benchmarks */
+static struct ctx {
+ struct bpf_loop_bench *skel;
+} ctx;
+
+static struct {
+ __u32 nr_loops;
+} args = {
+ .nr_loops = 10,
+};
+
+enum {
+ ARG_NR_LOOPS = 4000,
+};
+
+static const struct argp_option opts[] = {
+ { "nr_loops", ARG_NR_LOOPS, "nr_loops", 0,
+ "Set number of loops for the bpf_loop helper"},
+ {},
+};
+
+static error_t parse_arg(int key, char *arg, struct argp_state *state)
+{
+ switch (key) {
+ case ARG_NR_LOOPS:
+ args.nr_loops = strtol(arg, NULL, 10);
+ break;
+ default:
+ return ARGP_ERR_UNKNOWN;
+ }
+
+ return 0;
+}
+
+/* exported into benchmark runner */
+const struct argp bench_bpf_loop_argp = {
+ .options = opts,
+ .parser = parse_arg,
+};
+
+static void validate(void)
+{
+ if (env.consumer_cnt != 1) {
+ fprintf(stderr, "benchmark doesn't support multi-consumer!\n");
+ exit(1);
+ }
+}
+
+static void *producer(void *input)
+{
+ while (true)
+ /* trigger the bpf program */
+ syscall(__NR_getpgid);
+
+ return NULL;
+}
+
+static void *consumer(void *input)
+{
+ return NULL;
+}
+
+static void measure(struct bench_res *res)
+{
+ res->hits = atomic_swap(&ctx.skel->bss->hits, 0);
+}
+
+static void setup(void)
+{
+ struct bpf_link *link;
+
+ setup_libbpf();
+
+ ctx.skel = bpf_loop_bench__open_and_load();
+ if (!ctx.skel) {
+ fprintf(stderr, "failed to open skeleton\n");
+ exit(1);
+ }
+
+ link = bpf_program__attach(ctx.skel->progs.benchmark);
+ if (!link) {
+ fprintf(stderr, "failed to attach program!\n");
+ exit(1);
+ }
+
+ ctx.skel->bss->nr_loops = args.nr_loops;
+}
+
+const struct bench bench_bpf_loop = {
+ .name = "bpf-loop",
+ .validate = validate,
+ .setup = setup,
+ .producer_thread = producer,
+ .consumer_thread = consumer,
+ .measure = measure,
+ .report_progress = ops_report_progress,
+ .report_final = ops_report_final,
+};
--- /dev/null
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+source ./benchs/run_common.sh
+
+set -eufo pipefail
+
+for t in 1 4 8 12 16; do
+for i in 10 100 500 1000 5000 10000 50000 100000 500000 1000000; do
+subtitle "nr_loops: $i, nr_threads: $t"
+ summarize_ops "bpf_loop: " \
+ "$($RUN_BENCH -p $t --nr_loops $i bpf-loop)"
+ printf "\n"
+done
+done
echo "$*" | sed -E "s/.*Percentage\s=\s+([0-9]+\.[0-9]+).*/\1/"
}
+function ops()
+{
+ echo -n "throughput: "
+ echo -n "$*" | sed -E "s/.*throughput\s+([0-9]+\.[0-9]+ ± [0-9]+\.[0-9]+\sM\sops\/s).*/\1/"
+ echo -n -e ", latency: "
+ echo "$*" | sed -E "s/.*latency\s+([0-9]+\.[0-9]+\sns\/op).*/\1/"
+}
+
function total()
{
echo "$*" | sed -E "s/.*total operations\s+([0-9]+\.[0-9]+ ± [0-9]+\.[0-9]+M\/s).*/\1/"
printf "%-20s %s%%\n" "$bench" "$(percentage $summary)"
}
+function summarize_ops()
+{
+ bench="$1"
+ summary=$(echo $2 | tail -n1)
+ printf "%-20s %s\n" "$bench" "$(ops $summary)"
+}
+
function summarize_total()
{
bench="$1"
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+u32 nr_loops;
+long hits;
+
+static int empty_callback(__u32 index, void *data)
+{
+ return 0;
+}
+
+SEC("fentry/__x64_sys_getpgid")
+int benchmark(void *ctx)
+{
+ for (int i = 0; i < 1000; i++) {
+ bpf_loop(nr_loops, empty_callback, NULL, 0);
+
+ __sync_add_and_fetch(&hits, nr_loops);
+ }
+ return 0;
+}
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