linux/tools/testing/selftests/bpf/bench.c
Dave Marchevsky 2b4b2621fd selftests/bpf: Add benchmark for local_storage RCU Tasks Trace usage
This benchmark measures grace period latency and kthread cpu usage of
RCU Tasks Trace when many processes are creating/deleting BPF
local_storage. Intent here is to quantify improvement on these metrics
after Paul's recent RCU Tasks patches [0].

Specifically, fork 15k tasks which call a bpf prog that creates/destroys
task local_storage and sleep in a loop, resulting in many
call_rcu_tasks_trace calls.

To determine grace period latency, trace time elapsed between
rcu_tasks_trace_pregp_step and rcu_tasks_trace_postgp; for cpu usage
look at rcu_task_trace_kthread's stime in /proc/PID/stat.

On my virtualized test environment (Skylake, 8 cpus) benchmark results
demonstrate significant improvement:

BEFORE Paul's patches:

  SUMMARY tasks_trace grace period latency        avg 22298.551 us stddev 1302.165 us
  SUMMARY ticks per tasks_trace grace period      avg 2.291 stddev 0.324

AFTER Paul's patches:

  SUMMARY tasks_trace grace period latency        avg 16969.197 us  stddev 2525.053 us
  SUMMARY ticks per tasks_trace grace period      avg 1.146 stddev 0.178

Note that since these patches are not in bpf-next benchmarking was done
by cherry-picking this patch onto rcu tree.

  [0] https://lore.kernel.org/rcu/20220620225402.GA3842369@paulmck-ThinkPad-P17-Gen-1/

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20220705190018.3239050-1-davemarchevsky@fb.com
2022-07-07 16:35:21 +02:00

651 lines
18 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#define _GNU_SOURCE
#include <argp.h>
#include <linux/compiler.h>
#include <sys/time.h>
#include <sched.h>
#include <fcntl.h>
#include <pthread.h>
#include <sys/sysinfo.h>
#include <signal.h>
#include "bench.h"
#include "testing_helpers.h"
struct env env = {
.warmup_sec = 1,
.duration_sec = 5,
.affinity = false,
.consumer_cnt = 1,
.producer_cnt = 1,
};
static int libbpf_print_fn(enum libbpf_print_level level,
const char *format, va_list args)
{
if (level == LIBBPF_DEBUG && !env.verbose)
return 0;
return vfprintf(stderr, format, args);
}
void setup_libbpf(void)
{
libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
libbpf_set_print(libbpf_print_fn);
}
void false_hits_report_progress(int iter, struct bench_res *res, long delta_ns)
{
long total = res->false_hits + res->hits + res->drops;
printf("Iter %3d (%7.3lfus): ",
iter, (delta_ns - 1000000000) / 1000.0);
printf("%ld false hits of %ld total operations. Percentage = %2.2f %%\n",
res->false_hits, total, ((float)res->false_hits / total) * 100);
}
void false_hits_report_final(struct bench_res res[], int res_cnt)
{
long total_hits = 0, total_drops = 0, total_false_hits = 0, total_ops = 0;
int i;
for (i = 0; i < res_cnt; i++) {
total_hits += res[i].hits;
total_false_hits += res[i].false_hits;
total_drops += res[i].drops;
}
total_ops = total_hits + total_false_hits + total_drops;
printf("Summary: %ld false hits of %ld total operations. ",
total_false_hits, total_ops);
printf("Percentage = %2.2f %%\n",
((float)total_false_hits / total_ops) * 100);
}
void hits_drops_report_progress(int iter, struct bench_res *res, long delta_ns)
{
double hits_per_sec, drops_per_sec;
double hits_per_prod;
hits_per_sec = res->hits / 1000000.0 / (delta_ns / 1000000000.0);
hits_per_prod = hits_per_sec / env.producer_cnt;
drops_per_sec = res->drops / 1000000.0 / (delta_ns / 1000000000.0);
printf("Iter %3d (%7.3lfus): ",
iter, (delta_ns - 1000000000) / 1000.0);
printf("hits %8.3lfM/s (%7.3lfM/prod), drops %8.3lfM/s, total operations %8.3lfM/s\n",
hits_per_sec, hits_per_prod, drops_per_sec, hits_per_sec + drops_per_sec);
}
void
grace_period_latency_basic_stats(struct bench_res res[], int res_cnt, struct basic_stats *gp_stat)
{
int i;
memset(gp_stat, 0, sizeof(struct basic_stats));
for (i = 0; i < res_cnt; i++)
gp_stat->mean += res[i].gp_ns / 1000.0 / (double)res[i].gp_ct / (0.0 + res_cnt);
#define IT_MEAN_DIFF (res[i].gp_ns / 1000.0 / (double)res[i].gp_ct - gp_stat->mean)
if (res_cnt > 1) {
for (i = 0; i < res_cnt; i++)
gp_stat->stddev += (IT_MEAN_DIFF * IT_MEAN_DIFF) / (res_cnt - 1.0);
}
gp_stat->stddev = sqrt(gp_stat->stddev);
#undef IT_MEAN_DIFF
}
void
grace_period_ticks_basic_stats(struct bench_res res[], int res_cnt, struct basic_stats *gp_stat)
{
int i;
memset(gp_stat, 0, sizeof(struct basic_stats));
for (i = 0; i < res_cnt; i++)
gp_stat->mean += res[i].stime / (double)res[i].gp_ct / (0.0 + res_cnt);
#define IT_MEAN_DIFF (res[i].stime / (double)res[i].gp_ct - gp_stat->mean)
if (res_cnt > 1) {
for (i = 0; i < res_cnt; i++)
gp_stat->stddev += (IT_MEAN_DIFF * IT_MEAN_DIFF) / (res_cnt - 1.0);
}
gp_stat->stddev = sqrt(gp_stat->stddev);
#undef IT_MEAN_DIFF
}
void hits_drops_report_final(struct bench_res res[], int res_cnt)
{
int i;
double hits_mean = 0.0, drops_mean = 0.0, total_ops_mean = 0.0;
double hits_stddev = 0.0, drops_stddev = 0.0, total_ops_stddev = 0.0;
double total_ops;
for (i = 0; i < res_cnt; i++) {
hits_mean += res[i].hits / 1000000.0 / (0.0 + res_cnt);
drops_mean += res[i].drops / 1000000.0 / (0.0 + res_cnt);
}
total_ops_mean = hits_mean + drops_mean;
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);
drops_stddev += (drops_mean - res[i].drops / 1000000.0) *
(drops_mean - res[i].drops / 1000000.0) /
(res_cnt - 1.0);
total_ops = res[i].hits + res[i].drops;
total_ops_stddev += (total_ops_mean - total_ops / 1000000.0) *
(total_ops_mean - total_ops / 1000000.0) /
(res_cnt - 1.0);
}
hits_stddev = sqrt(hits_stddev);
drops_stddev = sqrt(drops_stddev);
total_ops_stddev = sqrt(total_ops_stddev);
}
printf("Summary: hits %8.3lf \u00B1 %5.3lfM/s (%7.3lfM/prod), ",
hits_mean, hits_stddev, hits_mean / env.producer_cnt);
printf("drops %8.3lf \u00B1 %5.3lfM/s, ",
drops_mean, drops_stddev);
printf("total operations %8.3lf \u00B1 %5.3lfM/s\n",
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);
}
void local_storage_report_progress(int iter, struct bench_res *res,
long delta_ns)
{
double important_hits_per_sec, hits_per_sec;
double delta_sec = delta_ns / 1000000000.0;
hits_per_sec = res->hits / 1000000.0 / delta_sec;
important_hits_per_sec = res->important_hits / 1000000.0 / delta_sec;
printf("Iter %3d (%7.3lfus): ", iter, (delta_ns - 1000000000) / 1000.0);
printf("hits %8.3lfM/s ", hits_per_sec);
printf("important_hits %8.3lfM/s\n", important_hits_per_sec);
}
void local_storage_report_final(struct bench_res res[], int res_cnt)
{
double important_hits_mean = 0.0, important_hits_stddev = 0.0;
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);
important_hits_mean += res[i].important_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);
important_hits_stddev +=
(important_hits_mean - res[i].important_hits / 1000000.0) *
(important_hits_mean - res[i].important_hits / 1000000.0) /
(res_cnt - 1.0);
}
hits_stddev = sqrt(hits_stddev);
important_hits_stddev = sqrt(important_hits_stddev);
}
printf("Summary: hits throughput %8.3lf \u00B1 %5.3lf M ops/s, ",
hits_mean, hits_stddev);
printf("hits latency %8.3lf ns/op, ", 1000.0 / hits_mean);
printf("important_hits throughput %8.3lf \u00B1 %5.3lf M ops/s\n",
important_hits_mean, important_hits_stddev);
}
const char *argp_program_version = "benchmark";
const char *argp_program_bug_address = "<bpf@vger.kernel.org>";
const char argp_program_doc[] =
"benchmark Generic benchmarking framework.\n"
"\n"
"This tool runs benchmarks.\n"
"\n"
"USAGE: benchmark <bench-name>\n"
"\n"
"EXAMPLES:\n"
" # run 'count-local' benchmark with 1 producer and 1 consumer\n"
" benchmark count-local\n"
" # run 'count-local' with 16 producer and 8 consumer thread, pinned to CPUs\n"
" benchmark -p16 -c8 -a count-local\n";
enum {
ARG_PROD_AFFINITY_SET = 1000,
ARG_CONS_AFFINITY_SET = 1001,
};
static const struct argp_option opts[] = {
{ "list", 'l', NULL, 0, "List available benchmarks"},
{ "duration", 'd', "SEC", 0, "Duration of benchmark, seconds"},
{ "warmup", 'w', "SEC", 0, "Warm-up period, seconds"},
{ "producers", 'p', "NUM", 0, "Number of producer threads"},
{ "consumers", 'c', "NUM", 0, "Number of consumer threads"},
{ "verbose", 'v', NULL, 0, "Verbose debug output"},
{ "affinity", 'a', NULL, 0, "Set consumer/producer thread affinity"},
{ "prod-affinity", ARG_PROD_AFFINITY_SET, "CPUSET", 0,
"Set of CPUs for producer threads; implies --affinity"},
{ "cons-affinity", ARG_CONS_AFFINITY_SET, "CPUSET", 0,
"Set of CPUs for consumer threads; implies --affinity"},
{},
};
extern struct argp bench_ringbufs_argp;
extern struct argp bench_bloom_map_argp;
extern struct argp bench_bpf_loop_argp;
extern struct argp bench_local_storage_argp;
extern struct argp bench_local_storage_rcu_tasks_trace_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_local_storage_argp, 0, "local_storage benchmark", 0 },
{ &bench_strncmp_argp, 0, "bpf_strncmp helper benchmark", 0 },
{ &bench_local_storage_rcu_tasks_trace_argp, 0,
"local_storage RCU Tasks Trace slowdown benchmark", 0 },
{},
};
static error_t parse_arg(int key, char *arg, struct argp_state *state)
{
static int pos_args;
switch (key) {
case 'v':
env.verbose = true;
break;
case 'l':
env.list = true;
break;
case 'd':
env.duration_sec = strtol(arg, NULL, 10);
if (env.duration_sec <= 0) {
fprintf(stderr, "Invalid duration: %s\n", arg);
argp_usage(state);
}
break;
case 'w':
env.warmup_sec = strtol(arg, NULL, 10);
if (env.warmup_sec <= 0) {
fprintf(stderr, "Invalid warm-up duration: %s\n", arg);
argp_usage(state);
}
break;
case 'p':
env.producer_cnt = strtol(arg, NULL, 10);
if (env.producer_cnt <= 0) {
fprintf(stderr, "Invalid producer count: %s\n", arg);
argp_usage(state);
}
break;
case 'c':
env.consumer_cnt = strtol(arg, NULL, 10);
if (env.consumer_cnt <= 0) {
fprintf(stderr, "Invalid consumer count: %s\n", arg);
argp_usage(state);
}
break;
case 'a':
env.affinity = true;
break;
case ARG_PROD_AFFINITY_SET:
env.affinity = true;
if (parse_num_list(arg, &env.prod_cpus.cpus,
&env.prod_cpus.cpus_len)) {
fprintf(stderr, "Invalid format of CPU set for producers.");
argp_usage(state);
}
break;
case ARG_CONS_AFFINITY_SET:
env.affinity = true;
if (parse_num_list(arg, &env.cons_cpus.cpus,
&env.cons_cpus.cpus_len)) {
fprintf(stderr, "Invalid format of CPU set for consumers.");
argp_usage(state);
}
break;
case ARGP_KEY_ARG:
if (pos_args++) {
fprintf(stderr,
"Unrecognized positional argument: %s\n", arg);
argp_usage(state);
}
env.bench_name = strdup(arg);
break;
default:
return ARGP_ERR_UNKNOWN;
}
return 0;
}
static void parse_cmdline_args(int argc, char **argv)
{
static const struct argp argp = {
.options = opts,
.parser = parse_arg,
.doc = argp_program_doc,
.children = bench_parsers,
};
if (argp_parse(&argp, argc, argv, 0, NULL, NULL))
exit(1);
if (!env.list && !env.bench_name) {
argp_help(&argp, stderr, ARGP_HELP_DOC, "bench");
exit(1);
}
}
static void collect_measurements(long delta_ns);
static __u64 last_time_ns;
static void sigalarm_handler(int signo)
{
long new_time_ns = get_time_ns();
long delta_ns = new_time_ns - last_time_ns;
collect_measurements(delta_ns);
last_time_ns = new_time_ns;
}
/* set up periodic 1-second timer */
static void setup_timer()
{
static struct sigaction sigalarm_action = {
.sa_handler = sigalarm_handler,
};
struct itimerval timer_settings = {};
int err;
last_time_ns = get_time_ns();
err = sigaction(SIGALRM, &sigalarm_action, NULL);
if (err < 0) {
fprintf(stderr, "failed to install SIGALRM handler: %d\n", -errno);
exit(1);
}
timer_settings.it_interval.tv_sec = 1;
timer_settings.it_value.tv_sec = 1;
err = setitimer(ITIMER_REAL, &timer_settings, NULL);
if (err < 0) {
fprintf(stderr, "failed to arm interval timer: %d\n", -errno);
exit(1);
}
}
static void set_thread_affinity(pthread_t thread, int cpu)
{
cpu_set_t cpuset;
CPU_ZERO(&cpuset);
CPU_SET(cpu, &cpuset);
if (pthread_setaffinity_np(thread, sizeof(cpuset), &cpuset)) {
fprintf(stderr, "setting affinity to CPU #%d failed: %d\n",
cpu, errno);
exit(1);
}
}
static int next_cpu(struct cpu_set *cpu_set)
{
if (cpu_set->cpus) {
int i;
/* find next available CPU */
for (i = cpu_set->next_cpu; i < cpu_set->cpus_len; i++) {
if (cpu_set->cpus[i]) {
cpu_set->next_cpu = i + 1;
return i;
}
}
fprintf(stderr, "Not enough CPUs specified, need CPU #%d or higher.\n", i);
exit(1);
}
return cpu_set->next_cpu++;
}
static struct bench_state {
int res_cnt;
struct bench_res *results;
pthread_t *consumers;
pthread_t *producers;
} state;
const struct bench *bench = NULL;
extern const struct bench bench_count_global;
extern const struct bench bench_count_local;
extern const struct bench bench_rename_base;
extern const struct bench bench_rename_kprobe;
extern const struct bench bench_rename_kretprobe;
extern const struct bench bench_rename_rawtp;
extern const struct bench bench_rename_fentry;
extern const struct bench bench_rename_fexit;
extern const struct bench bench_trig_base;
extern const struct bench bench_trig_tp;
extern const struct bench bench_trig_rawtp;
extern const struct bench bench_trig_kprobe;
extern const struct bench bench_trig_fentry;
extern const struct bench bench_trig_fentry_sleep;
extern const struct bench bench_trig_fmodret;
extern const struct bench bench_trig_uprobe_base;
extern const struct bench bench_trig_uprobe_with_nop;
extern const struct bench bench_trig_uretprobe_with_nop;
extern const struct bench bench_trig_uprobe_without_nop;
extern const struct bench bench_trig_uretprobe_without_nop;
extern const struct bench bench_rb_libbpf;
extern const struct bench bench_rb_custom;
extern const struct bench bench_pb_libbpf;
extern const struct bench bench_pb_custom;
extern const struct bench bench_bloom_lookup;
extern const struct bench bench_bloom_update;
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;
extern const struct bench bench_bpf_hashmap_full_update;
extern const struct bench bench_local_storage_cache_seq_get;
extern const struct bench bench_local_storage_cache_interleaved_get;
extern const struct bench bench_local_storage_cache_hashmap_control;
extern const struct bench bench_local_storage_tasks_trace;
static const struct bench *benchs[] = {
&bench_count_global,
&bench_count_local,
&bench_rename_base,
&bench_rename_kprobe,
&bench_rename_kretprobe,
&bench_rename_rawtp,
&bench_rename_fentry,
&bench_rename_fexit,
&bench_trig_base,
&bench_trig_tp,
&bench_trig_rawtp,
&bench_trig_kprobe,
&bench_trig_fentry,
&bench_trig_fentry_sleep,
&bench_trig_fmodret,
&bench_trig_uprobe_base,
&bench_trig_uprobe_with_nop,
&bench_trig_uretprobe_with_nop,
&bench_trig_uprobe_without_nop,
&bench_trig_uretprobe_without_nop,
&bench_rb_libbpf,
&bench_rb_custom,
&bench_pb_libbpf,
&bench_pb_custom,
&bench_bloom_lookup,
&bench_bloom_update,
&bench_bloom_false_positive,
&bench_hashmap_without_bloom,
&bench_hashmap_with_bloom,
&bench_bpf_loop,
&bench_strncmp_no_helper,
&bench_strncmp_helper,
&bench_bpf_hashmap_full_update,
&bench_local_storage_cache_seq_get,
&bench_local_storage_cache_interleaved_get,
&bench_local_storage_cache_hashmap_control,
&bench_local_storage_tasks_trace,
};
static void setup_benchmark()
{
int i, err;
if (!env.bench_name) {
fprintf(stderr, "benchmark name is not specified\n");
exit(1);
}
for (i = 0; i < ARRAY_SIZE(benchs); i++) {
if (strcmp(benchs[i]->name, env.bench_name) == 0) {
bench = benchs[i];
break;
}
}
if (!bench) {
fprintf(stderr, "benchmark '%s' not found\n", env.bench_name);
exit(1);
}
printf("Setting up benchmark '%s'...\n", bench->name);
state.producers = calloc(env.producer_cnt, sizeof(*state.producers));
state.consumers = calloc(env.consumer_cnt, sizeof(*state.consumers));
state.results = calloc(env.duration_sec + env.warmup_sec + 2,
sizeof(*state.results));
if (!state.producers || !state.consumers || !state.results)
exit(1);
if (bench->validate)
bench->validate();
if (bench->setup)
bench->setup();
for (i = 0; i < env.consumer_cnt; i++) {
err = pthread_create(&state.consumers[i], NULL,
bench->consumer_thread, (void *)(long)i);
if (err) {
fprintf(stderr, "failed to create consumer thread #%d: %d\n",
i, -errno);
exit(1);
}
if (env.affinity)
set_thread_affinity(state.consumers[i],
next_cpu(&env.cons_cpus));
}
/* unless explicit producer CPU list is specified, continue after
* last consumer CPU
*/
if (!env.prod_cpus.cpus)
env.prod_cpus.next_cpu = env.cons_cpus.next_cpu;
for (i = 0; i < env.producer_cnt; i++) {
err = pthread_create(&state.producers[i], NULL,
bench->producer_thread, (void *)(long)i);
if (err) {
fprintf(stderr, "failed to create producer thread #%d: %d\n",
i, -errno);
exit(1);
}
if (env.affinity)
set_thread_affinity(state.producers[i],
next_cpu(&env.prod_cpus));
}
printf("Benchmark '%s' started.\n", bench->name);
}
static pthread_mutex_t bench_done_mtx = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t bench_done = PTHREAD_COND_INITIALIZER;
static void collect_measurements(long delta_ns) {
int iter = state.res_cnt++;
struct bench_res *res = &state.results[iter];
bench->measure(res);
if (bench->report_progress)
bench->report_progress(iter, res, delta_ns);
if (iter == env.duration_sec + env.warmup_sec) {
pthread_mutex_lock(&bench_done_mtx);
pthread_cond_signal(&bench_done);
pthread_mutex_unlock(&bench_done_mtx);
}
}
int main(int argc, char **argv)
{
parse_cmdline_args(argc, argv);
if (env.list) {
int i;
printf("Available benchmarks:\n");
for (i = 0; i < ARRAY_SIZE(benchs); i++) {
printf("- %s\n", benchs[i]->name);
}
return 0;
}
setup_benchmark();
setup_timer();
pthread_mutex_lock(&bench_done_mtx);
pthread_cond_wait(&bench_done, &bench_done_mtx);
pthread_mutex_unlock(&bench_done_mtx);
if (bench->report_final)
/* skip first sample */
bench->report_final(state.results + env.warmup_sec,
state.res_cnt - env.warmup_sec);
return 0;
}