
It is sometimes desirable to be able to trigger BPF program from user-space with minimal overhead. sys_enter would seem to be a good candidate, yet in a lot of cases there will be a lot of noise from syscalls triggered by other processes on the system. So while searching for low-overhead alternative, I've stumbled upon getpgid() syscall, which seems to be specific enough to not suffer from accidental syscall by other apps. This set of benchmarks compares tp, raw_tp w/ filtering by syscall ID, kprobe, fentry and fmod_ret with returning error (so that syscall would not be executed), to determine the lowest-overhead way. Here are results on my machine (using benchs/run_bench_trigger.sh script): base : 9.200 ± 0.319M/s tp : 6.690 ± 0.125M/s rawtp : 8.571 ± 0.214M/s kprobe : 6.431 ± 0.048M/s fentry : 8.955 ± 0.241M/s fmodret : 8.903 ± 0.135M/s So it seems like fmodret doesn't give much benefit for such lightweight syscall. Raw tracepoint is pretty decent despite additional filtering logic, but it will be called for any other syscall in the system, which rules it out. Fentry, though, seems to be adding the least amoung of overhead and achieves 97.3% of performance of baseline no-BPF-attached syscall. Using getpgid() seems to be preferable to set_task_comm() approach from test_overhead, as it's about 2.35x faster in a baseline performance. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200512192445.2351848-5-andriin@fb.com
450 lines
11 KiB
C
450 lines
11 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 <sys/resource.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);
|
|
}
|
|
|
|
static int bump_memlock_rlimit(void)
|
|
{
|
|
struct rlimit rlim_new = {
|
|
.rlim_cur = RLIM_INFINITY,
|
|
.rlim_max = RLIM_INFINITY,
|
|
};
|
|
|
|
return setrlimit(RLIMIT_MEMLOCK, &rlim_new);
|
|
}
|
|
|
|
void setup_libbpf()
|
|
{
|
|
int err;
|
|
|
|
libbpf_set_print(libbpf_print_fn);
|
|
|
|
err = bump_memlock_rlimit();
|
|
if (err)
|
|
fprintf(stderr, "failed to increase RLIMIT_MEMLOCK: %d", err);
|
|
}
|
|
|
|
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\n",
|
|
hits_per_sec, hits_per_prod, drops_per_sec);
|
|
}
|
|
|
|
void hits_drops_report_final(struct bench_res res[], int res_cnt)
|
|
{
|
|
int i;
|
|
double hits_mean = 0.0, drops_mean = 0.0;
|
|
double hits_stddev = 0.0, drops_stddev = 0.0;
|
|
|
|
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);
|
|
}
|
|
|
|
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);
|
|
}
|
|
hits_stddev = sqrt(hits_stddev);
|
|
drops_stddev = sqrt(drops_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\n",
|
|
drops_mean, drops_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"},
|
|
{},
|
|
};
|
|
|
|
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,
|
|
};
|
|
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 SIGALARM 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_rename_fmodret;
|
|
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_fmodret;
|
|
|
|
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_rename_fmodret,
|
|
&bench_trig_base,
|
|
&bench_trig_tp,
|
|
&bench_trig_rawtp,
|
|
&bench_trig_kprobe,
|
|
&bench_trig_fentry,
|
|
&bench_trig_fmodret,
|
|
};
|
|
|
|
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;
|
|
}
|
|
|